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1

Microscale Experiments in the Organic Chemistry Laboratory.  

ERIC Educational Resources Information Center

Discusses the advent of microscale experiments within undergraduate organic chemistry laboratories mainly resulting from environmental safety concerns involving waste disposal. Considers the cost savings in purchasing less reagents and chemicals, the typical glassware and apparatus, the reduced hazards from elimination of open flames, and other…

Williamson, Kenneth L.

1991-01-01

2

Cocrystal Controlled Solid-State Synthesis: A Green Chemistry Experiment for Undergraduate Organic Chemistry  

ERIC Educational Resources Information Center

Green chemistry has become an important area of concern for all chemists from practitioners in the pharmaceutical industry to professors and the students they teach and is now being incorporated into lectures of general and organic chemistry courses. However, there are relatively few green chemistry experiments that are easily incorporated into…

Cheney, Miranda L.; Zaworotko, Michael J.; Beaton, Steve; Singer, Robert D.

2008-01-01

3

An Organic Chemistry Experiment for Forensic Science Majors.  

ERIC Educational Resources Information Center

The laboratory experiment described here is intended to be of use to the forensic science major enrolled in a course in organic chemistry. The experiment is the use of thin-layer chromotography for qualitative analysis, specifically for the identification of drugs. (Author/SA)

Rothchild, Robert

1979-01-01

4

Biodiesel Synthesis and Evaluation: An Organic Chemistry Experiment  

ERIC Educational Resources Information Center

A new lab esterification reaction based on biodiesel preparation and viscosity, which provides a model experience of industrial process to understand oxidation of vicinal alcohols by periodic acid, is presented. This new desertification experiment and periodate analysis of glycerol for the introductory organic chemistry laboratory provides an…

Bucholtz, Ehren C.

2007-01-01

5

Biodiesel from Seeds: An Experiment for Organic Chemistry  

ERIC Educational Resources Information Center

Plants can store the chemical energy required by their developing offspring in the form of triglycerides. These lipids can be isolated from seeds and then converted into biodiesel through a transesterification reaction. This second-year undergraduate organic chemistry laboratory experiment exemplifies the conversion of an agricultural energy…

Goldstein, Steven W.

2014-01-01

6

ORGANIC CHEMISTRY UCLA Organic Chemistry Faculty  

E-print Network

ORGANIC CHEMISTRY UCLA Organic Chemistry Faculty perform research in molecular machines, exotic CHEMISTRY FACULTY RESEARCH INTERESTS Anne M. Andrews, Professor-in-Residence: Understanding how areas of interest include cross- coupling reactions, green chemistry, heterocycle synthesis, and natural

Levine, Alex J.

7

An Enzyme Kinetics Experiment for the Undergraduate Organic Chemistry Laboratory  

ERIC Educational Resources Information Center

An experiment using [superscript 1]H NMR spectroscopy to observe the kinetics of the acylase 1-catalyzed hydrolysis of "N"-acetyl-DL-methionine has been developed for the organic laboratory. The L-enantiomer of the reactant is hydrolyzed completely in less than 2 h, and [superscript 1]H NMR spectroscopic data from a single sample can be worked up…

Olsen, Robert J.; Olsen, Julie A.; Giles, Greta A.

2010-01-01

8

Solvent-Free Wittig Reaction: A Green Organic Chemistry Laboratory Experiment  

ERIC Educational Resources Information Center

Some Wittig reactions can be carried out by grinding the reactants in a mortar with a pestle for about 20 minutes, as per investigation. A laboratory experiment involving a solvent-free Wittig reaction that can be completed in a three-hour sophomore organic chemistry laboratory class period, are developed.

Leung, Sam H.; Angel, Stephen A.

2004-01-01

9

The Synthesis of a Cockroach Pheromone: An Experiment for the Second-Year Organic Chemistry Laboratory  

ERIC Educational Resources Information Center

This experiment describes the synthesis of gentisyl quinone isovalerate, or blattellaquinone, a sex pheromone of the German cockroach that was isolated and identified in 2005. The synthesis is appropriate for the second semester of a second-year organic chemistry laboratory course. It can be completed in two, three-hour laboratory periods and uses…

Feist, Patty L.

2008-01-01

10

Teaching Catalytic Antibodies to Undergraduate Students: An Organic Chemistry Lab Experiment  

NASA Astrophysics Data System (ADS)

Only 13 years ago, few believed that antibodies could be catalytic or that any protein could be made to order to perform a catalytic task. The field has quickly matured from initial proof of concept and demonstration of fundamental enzyme-like characteristics to one in which antibodies have catalyzed an extremely broad range of organic transformations. Now that the first catalytic antibody is commercially available, it is possible to bring these novel biocatalysts into the classroom so every student can gain hands-on experience and carry out experiments on the cutting edge of scientific discovery. This lab project deals with antibody-catalyzed aldol condensations. It includes the (i) synthesis of substrate and product; (ii) HPLC characterization of the antibody-catalyzed reaction; (iii) titration of the antibody active-site; and (iv) analysis of the kinetics of the antibody-catalyzed reaction. The lab project provides training not only in biocatalysis but in a number of related aspects of chemical and biochemical research, including organic synthesis, mechanistic organic chemistry, and chemical kinetics. Students will learn the use of various experimental techniques, such as UV-vis spectroscopy and HPLC, to monitor chemical reactions and determine kinetic parameters. They will be exposed to concepts and terminology of bioorganic chemistry, such as protein structure and function, inhibition and active-site titration, and basic principles of biocatalysis.

Shulman, Avidor; Keinan, Ehud; Shabat, Doron; Barbas, Carlos F., III

1999-07-01

11

Organic Chemistry Resources Worldwide  

NSDL National Science Digital Library

Organic Chemistry Worldwide is an excellent organic chemistry metasite that is not to be missed. Geared toward synthetic organic chemists involved in academic or industrial research, Organic Chemistry Resources Worldwide has a mission to collect and independently annotate "all useful organic chemistry sites and to present them in an intuitive way." This extensive metasite is divided into sections on literature, laboratory resources, spectroscopy and spectrometry, nomenclature and teaching, and conferences and organizations. The Literature section contains links to over 75 journals (some restricted access), 14 free databases (and many more commercial), dissertation collections, reviews, guides, patents, and current awareness sources. Examples of resources for laboratory work include links to chemical product databases, laboratory safety bulletins (.pdf), products and services, etc. Highlights of the site are an in-depth section on mass spectrometry, with links to publications and databases, and a plethora of links to organic chemistry labs worldwide, from Armenia to Uruguay.

Van Aken, Koen

1996-01-01

12

Detecting Complex Organic Compounds Using the SAM Wet Chemistry Experiment on Mars  

NASA Astrophysics Data System (ADS)

The search for organic molecules on Mars can provide important first clues of abiotic chemistry and/or extinct or extant biota on the planet. Gas Chromatography Mass Spectrometry (GC-MS) is currently the most relevant space-compatible analytical tool for the detection of organic compounds. Nevertheless, GC separation is intrinsically restricted to volatile molecules, and many molecules of astrobiological interest are chromatographically refractory or polar. To analyze these organics such as amino acids, nucleobases and carboxylic acids in the Martian regolith, an additional derivatization step is required to transform them into volatile derivatives that are amenable to GC analysis. As part of the Sample Analysis at Mars (SAM) experiment onboard Mars Science Laboratory (MSL) Curiosity rover, a single-step protocol of extraction and chemical derivatization with the silylating reagent N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide (MTBSTFA) has been developed to reach a wide range of astrobiology-relevant refractory organic molecules (Mahaffy et al. 2012; Stalport et al. 2012). Seven cups in the SAM instrument are devoted to MTBSTFA derivatization. However, this chemical reaction adds a protective silyl group in place of each labile hydrogen, which makes the molecule non-identifiable in common mass spectra libraries. Therefore, we have created an extended library of mass spectra of MTBSTFA derivatized compounds of interest, considering their potential occurrence in Mars soils. We then looked specifically for MTBSTFA derivatized compounds using the existing and the newly created library, in various Mars analog soils. To enable a more accurate interpretation of the in situ derivatization GC-MS results that will be obtained by SAM, the lab experiments were performed as close as possible to the SAM flight instrument experimental conditions. Our first derivatization experiments display promising results, the laboratory system permitting an extraction and detection of several proteinogenic amino acids and carboxylic acids from Martian analog materials. Preliminary results show a lack of derivatized organic molecules in hydrated solid samples however, where the MTBSTFA reagent possibly reacts preferentially with the water from hydrated minerals (Stalport et al. 2012). This result shows the importance of a complete understanding of the MTBSTFA reaction depending on the nature of the soil and will help guide the selection of optimal samples for the SAM wet chemistry on Mars.

Freissinet, C.; Buch, A.; Glavin, D. P.; Brault, A.; Eigenbrode, J. L.; Kashyap, S.; Martin, M. G.; Miller, K.; Mahaffy, P. R.; Team, M.

2013-12-01

13

Peer Mentoring in the General Chemistry and Organic Chemistry Laboratories. The Pinacol Rearrangement: An Exercise in NMR and IR Spectroscopy for General Chemistry and Organic Chemistry Laboratories  

Microsoft Academic Search

This article describes a discovery experiment for general chemistry and organic chemistry labs. Although the pinacol rearrangement has been employed in undergraduate organic laboratories before, in this application organic chemistry students act as mentors to students of general chemistry. Students work together using distillation---a new technique for the general chemistry students and a basic one for the organic students---to isolate

Caleb A. Arrington; Jameica B. Hill; Ramin Radfar; David M. Whisnant; Charles G. Bass

2008-01-01

14

Extraction and [superscript 1]H NMR Analysis of Fats from Convenience Foods: A Laboratory Experiment for Organic Chemistry  

ERIC Educational Resources Information Center

The extraction and analysis of fats from convenience foods (crackers, cookies, chips, candies) has been developed as an experiment for a second-year undergraduate organic chemistry laboratory course. Students gravimetrically determine the fat content per serving and then perform a [superscript 1]H NMR analysis of the recovered fat to determine the…

Hartel, Aaron M.; Moore, Amy C.

2014-01-01

15

CHEMISTRY 324W ORGANIC LABORATORY  

E-print Network

1 Fall 2010 CHEMISTRY 324W ORGANIC LABORATORY Course Information Title: Chemistry 324W, Organic for multiple chemistry classes) $5 key deposit fee (refunded at end of semester with return of key) Course a scientific paper consistent with the format of the Journal of Organic Chemistry, American Chemical Society. 7

Wagner, Diane

16

Exploring Atmospheric Aqueous Chemistry (and Secondary Organic Aerosol Formation) through OH Radical Oxidation Experiments, Droplet Evaporation and Chemical Modeling  

NASA Astrophysics Data System (ADS)

Gas phase photochemistry fragments and oxidizes organic emissions, making water-soluble organics ubiquitous in the atmosphere. My group and others have found that several water-soluble compounds react further in the aqueous phase forming low volatility products under atmospherically-relevant conditions (i.e., in clouds, fogs and wet aerosols). Thus, secondary organic aerosol can form as a result of gas followed by aqueous chemistry (aqSOA). We have used aqueous OH radical oxidation experiments coupled with product analysis and chemical modeling to validate and refine the aqueous chemistry of glyoxal, methylglyoxal, glycolaldehyde, and acetic acid. The resulting chemical model has provided insights into the differences between oxidation chemistry in clouds and in wet aerosols. Further, we conducted droplet evaporation experiments to characterize the volatility of the products. Most recently, we have conducted aqueous OH radical oxidation experiments with ambient mixtures of water-soluble gases to identify additional atmospherically-important precursors and products. Specifically, we scrubbed water-soluble gases from the ambient air in the Po Valley, Italy using four mist chambers in parallel, operating at 25-30 L min-1. Aqueous OH radical oxidation experiments and control experiments were conducted with these mixtures (total organic carbon ? 100 ?M-C). OH radicals (3.5E-2 ?M [OH] s-1) were generated by photolyzing H2O2. Precursors and products were characterized using electrospray ionization mass spectrometry (ESI-MS), ion chromatography (IC), IC-ESI-MS, and ultra high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Chemical modeling suggests that organic acids (e.g., oxalate, pyruvate, glycolate) are major products of OH radical oxidation at cloud-relevant concentrations, whereas organic radical - radical reactions result in the formation of oligomers in wet aerosols. Products of cloud chemistry and droplet evaporation have effective vapor pressures that are orders of magnitude lower when ammonium hydroxide is present (pH 7) than without (at lower pH). In Po Valley experiments, nitrogen-containing organics were prominent precursors and intermediates. Pyruvate and oxalate were among the products. Importantly, formation of aqSOA helps to explain the high O/C ratios found in atmospheric aerosols. While uncertainties remain large, global modeling suggests that aqSOA is comparable in magnitude to SOA formed through gas phase chemistry and vapor pressure driven partitioning (gasSOA).

Turpin, B. J.; Kirkland, J. R.; Lim, Y. B.; Ortiz-Montalvo, D. L.; Sullivan, A.; Häkkinen, S.; Schwier, A. N.; Tan, Y.; McNeill, V. F.; Collett, J. L.; Skog, K.; Keutsch, F. N.; Sareen, N.; Carlton, A. G.; Decesari, S.; Facchini, C.

2013-12-01

17

Perspectives on Computational Organic Chemistry  

PubMed Central

The author reviews how his early love for theoretical organic chemistry led to experimental research and the extended search for quantitative correlations between experiment and quantum calculations. The experimental work led to ion pair acidities of alkali-organic compounds and most recently to equilibria and reactions of lithium and cesium enolates in THF. This chemistry is now being modeled by ab initio calculations. An important consideration is the treatment of solvation in which coordination of the alkali cation with the ether solvent plays a major role. PMID:19518150

Streitwieser, Andrew

2009-01-01

18

Chemistry 675 Advanced Organic Chemistry  

E-print Network

. Chisholm 4-006 CST jdchisho@syr.edu 443-6894 Office Hours: By appointment, between 9 AM and 5 PM Course in my office (CST 4-006) or my mailbox in the chemistry office (CST 1-014). Late problem sets will have

Doyle, Robert

19

Online organic chemistry  

NASA Astrophysics Data System (ADS)

This is a comprehensive study of the many facets of an entirely online organic chemistry course. Online homework with structure-drawing capabilities was found to be more effective than written homework. Online lecture was found to be just as effective as in-person lecture, and students prefer an online lecture format with shorter Webcasts. Online office hours were found to be effective, and discussion sessions can be placed online as well. A model was created that explains 36.1% of student performance based on GPA, ACT Math score, grade in previous chemistry course, and attendance at various forms of discussion. Online exams have been created which test problem-solving skills and is instantly gradable. In these exams, students can submit answers until time runs out for different numbers of points. These facets were combined effectively to create an entirely online organic chemistry course which students prefer over the in-person alternative. Lastly, there is a vision for where online organic chemistry is going and what can be done to improve education for all.

Janowicz, Philip A.

20

The Birthday of Organic Chemistry.  

ERIC Educational Resources Information Center

Describes how the synthesis of urea, 150 years ago, was a major factor in breaking the artificial barrier that existed between organic and inorganic chemistry, and this contributed to the rapid growth of organic chemistry. (GA)

Benfey, Otto Theodor; Kaufman, George B.

1979-01-01

21

Organic Chemistry, 5th Edition  

NSDL National Science Digital Library

Finds ChemEd DL resources related to the sections of the Organic Chemistry textbook, Organic Chemistry, 5th Edition, by William H. Brown, Christopher S. Foote, Brent L. Iverson, Eric Anslyn published by Brooks/Cole, 2009.

22

An NMR Study of Isotope Effect on Keto-Enol Tautomerization: A Physical Organic Chemistry Experiment  

ERIC Educational Resources Information Center

Isotope substitution often affects the rate of an organic reaction and can be used to reveal the underlying mechanism. A series of experiments that use (super 1)H NMR to determine primary and secondary isotope effects, activation parameters, and the regioselectivity of butanone enolization are described.

Atkinson, D.; Chechik, V.

2004-01-01

23

The Separation and Identification of Two Unknown Solid Organic Compounds: An Experiment for the Sophomore Organic Chemistry Laboratory  

ERIC Educational Resources Information Center

Segregation and recognition of two unfamiliar concrete organic compounds are achieved through microscale flash chromatography and spectroscopy plus melting point verifications respectively. This inexpensive and harmless microscale experiment for sophomore students ensures exercise in chromatographic and spectroscopic methods.

Feist, Patty L.

2004-01-01

24

Synthesis and Small Molecule Exchange Studies of a Magnesium Bisformate Metal-Organic Framework: An Experiment in Host-Guest Chemistry for the Undergraduate Laboratory  

ERIC Educational Resources Information Center

concepts of host-guest chemistry and size exclusion in porous metal-organic frameworks (MOFs). The experiment has been successfully carried out in both introductory and advanced-level inorganic chemistry laboratories. Students synthesized the porous MOF, alpha-Mg[subscript…

Rood, Jeffrey A.; Henderson, Kenneth W.

2013-01-01

25

Improving the Effectiveness of Organic Chemistry Experiments through Multimedia Teaching Materials for Junior High School Students  

ERIC Educational Resources Information Center

The purpose of the study aimed to explore the effects of three different forms of the multimedia teaching materials on the achievements and attitudes of junior high school students in a chemistry laboratory context. The three forms of the multimedia teaching materials, static pictures, video, and animation, were employed to teach chemistry

Lou, Shi-Jer; Lin, Hui-Chen; Shih, Ru-Chu; Tseng, Kuo-Hung

2012-01-01

26

Chemistry 675 (CHE 675) Advanced Organic Chemistry  

E-print Network

, with required reading assignments given on the syllabus. Learning outcomes Upon completion of this course, a student should have mastered the following areas / skills: Understand the structure of organic molecules of interest Gain an appreciation of the current state of mechanistic investigation in chemistry and related

Mather, Patrick T.

27

Organic Chemistry and Your Cellphone  

NSDL National Science Digital Library

The National Center for Case Study Teaching in Science releases new and helpful teaching materials on a regular basis. This recent addition to the Center's great resources deals with organic chemistry and cellphones. Crafted by Courtney Meyet and Richard Hooley of the University of California, Riverside, this case study guides students "through a systematic exploration of the synthesis and properties of polyphenylene vinylene." The whole experience starts with a classic article from Nature magazine and includes a PowerPoint presentation, a series of group questions, and other activities. The resources here are intended for an undergraduate audience and persons with an interest in organic reactions, organic materials, and polymers will find that this resource is most efficacious.

Hooley, Richard J.; Meyet, Courtney E.

2013-09-16

28

Organic Chemistry for the Gifted.  

ERIC Educational Resources Information Center

In response to a serious shortage of chemists in South Africa, gifted secondary school students are enrolled in an enrichment program in organic chemistry and encouraged to consider chemistry or one of its related fields as a career. The introductory portion of the program involves approximately 90 hours over a 3-year period while the advanced…

deBeer, W. H. J.

29

Diastereoselectivity In The Reduction Of Alpha-Hydroxyketones: An Experiment For The Chemistry Major Organic Laboratory  

ERIC Educational Resources Information Center

An experiment is developed that requires the use of the NMR spectrometer via a NOESY1D experiment to determine the diastereoselectivity in the reduction of alpha-methylbenzoin with various reducing agents. Students must synthesize racemic alpha-hydroxyketones, perform reductions under chelating and non-chelating conditions, and quantitatively…

Ball, David B.

2006-01-01

30

Determination of the Rotational Barrier for Kinetically Stable Conformational Isomers via NMR and 2D TLC: An Introductory Organic Chemistry Experiment  

ERIC Educational Resources Information Center

An experiment to determine the rotational barrier about a C[subscript aryl]-N[subscript imide] single bond that is suitable for first-semester organic chemistry students is presented. The investigation begins with the one-step synthesis of a N,N'-diaryl naphthalene diimide, which exists as two room temperature-stable atropisomers (syn and anti).…

Rushton, Gregory T.; Burns, William G.; Lavin, Judi M.; Chong, Yong S.; Pellechia, Perry; Shimizu, Ken D.

2007-01-01

31

Mass spectrometry. [in organic chemistry  

NASA Technical Reports Server (NTRS)

A review of mass spectrometry in organic chemistry is given, dealing with advances in instrumentation and computer techniques, selected topics in gas-phase ion chemistry, and applications in such fields as biomedicine, natural-product studies, and environmental pollution analysis. Innovative techniques and instrumentation are discussed, along with chromatographic-mass spectrometric on-line computer techniques, mass spectral interpretation and management techniques, and such topics in gas-phase ion chemistry as electron-impact ionization and decomposition, photoionization, field ionization and desorption, high-pressure mass spectrometry, ion cyclotron resonance, and isomerization reactions of organic ions. Applications of mass spectrometry are examined with respect to bio-oligomers and their constituents, biomedically important substances, microbiology, environmental organic analysis, and organic geochemistry.

Burlingame, A. L.; Shackleton, C. H. L.; Howe, I.; Chizhov, O. S.

1978-01-01

32

Soil Organic Chemistry.  

ERIC Educational Resources Information Center

A brief review is presented of some of the organic compounds and reactions that occur in soil. Included are nitrogenous compounds, compounds of phosphorus and sulfur, carbohydrates, phenolic compounds, and aliphatic acids. (BB)

Anderson, G.

1979-01-01

33

Chemistry 685 (CHE 685) Advanced Organic Chemistry: Organic Reaction Mechanisms and Molecular Interactions  

E-print Network

Chemistry 685 (CHE 685) Advanced Organic Chemistry: Organic Reaction Mechanisms and Molecular and physical chemistry Course description and rationale CHE685 is a graduate-level organic chemistry course. These two courses focus on physical organic chemistry, which deals with the structure and reactivity

Mather, Patrick T.

34

Organic chemistry in meteorites  

NASA Astrophysics Data System (ADS)

Carbonaceous chondrites contain a suite of soluble organic compounds that possess characteristics that help to understand their formation and to trace back the early history of the solar system. Relative amino acid abundances can be used to discriminate between different parent bodies. The Tagish Lake meteorite is a unique sample from a new type of solar system object that will help to further constrain the physical and chemical conditions found on parent bodies. Enantiomeric excesses have been detected in nonbiological amino acids in the Murchison and Murray meteorites that are still difficult to explain in the current scenario for the synthesis of extraterrestrial amino acids. Finally, new classes of compounds, dipeptides and sugar-related molecules, have been detected in CM carbonaceous chondrites.

Botta, Oliver

2002-11-01

35

Experiments in Electroanalytical Chemistry  

NSDL National Science Digital Library

This website offers educators a set of eight classical electroanalytical experiments suitable for use in a quantitative analysis, instrumental analysis, or electrochemistry course. The materials should be useful for advanced undergraduates and beginning graduate students. Experiments include coulometric, conductometric, and potentiometric titrations, stripping analysis, flow injection analysis, and polarography. It is important to note that several of the experiments use mercury or mercury coated electrodes which present safety concerns.

2011-05-30

36

Organic Chemistry Self Instructional Package 2: Methane.  

ERIC Educational Resources Information Center

This booklet, one of a series of 17 developed at Prince George's Community College, Largo, Maryland, provides an individualized, self-paced undergraduate organic chemistry instruction module designed to augment any course in organic chemistry but particularly those taught using the text "Organic Chemistry" by Morrison and Boyd. The entire series…

Zdravkovich, V.

37

Headspace GC-MS Analysis of Halogenated Volatile Organic Compounds in Aqueous Samples: An Experiment for General Chemistry Laboratory  

ERIC Educational Resources Information Center

Analysis of halogenated volatile organic compounds (HVOCs) by GC-MS demonstrates the use of instrumentation in the environmental analysis of pollutant molecules and enhances student understanding of stable isotopes in nature. In this experiment, students separated and identified several HVOCs that have been implicated as industrial groundwater…

Keller, John W.; Fabbri, Cindy E.

2012-01-01

38

Using Artificial Soil and Dry-Column Flash Chromatography to Simulate Organic Substance Leaching Process: A Colorful Environmental Chemistry Experiment  

ERIC Educational Resources Information Center

Soil is an important and complex environmental compartment and soil contamination contributes to the pollution of aquifers and other water basins. A simple and low-cost experiment is described in which the mobility of three organic compounds in an artificial soil is examined using dry-column flash chromatography. The compounds were applied on top…

de Avellar, Isa G. J.; Cotta, Tais A. P. G.; Neder, Amarilis de V. Finageiv

2012-01-01

39

The experiments in this course are examples of real-life problems which make use of organic chemistry in various ways and have impact on diverse businesses and industries. Each  

E-print Network

Overview The experiments in this course are examples of real-life problems which make use of organic chemistry in various ways and have impact on diverse businesses and industries. Each experiment participants have been changed! The aim of each experiment is for you to provide a solution to the problem

Houston, Paul L.

40

Caring for the Environment while Teaching Organic Chemistry  

ERIC Educational Resources Information Center

A comprehensive program in the field of green chemistry, which concentrates on processing and managing of wastes produced during laboratory experiments, is presented. The primary aim of the program is to instill a sense of responsibility and a concern for the environment through organic chemistry education.

Santos, Elvira Santos; Gavilan Garcia, Irma Cruz; Lejarazo Gomez, Eva Florencia

2004-01-01

41

Hydrothermal organic synthesis experiments  

NASA Technical Reports Server (NTRS)

The serious scientific debate about spontaneous generation which raged for centuries reached a climax in the nineteenth century with the work of Spallanzani, Schwann, Tyndall, and Pasteur. These investigators demonstrated that spontaneous generation from dead organic matter does not occur. Although no aspects of these experiments addressed the issue of whether organic compounds could be synthesized abiotically, the impact of the experiments was great enough to cause many investigators to assume that life and its organic compounds were somehow fundamentally different than inorganic compounds. Meanwhile, other nineteenth-century investigators were showing that organic compounds could indeed be synthesized from inorganic compounds. In 1828 Friedrich Wohler synthesized urea in an attempt to form ammonium cyanate by heating a solution containing ammonia and cyanic acid. This experiment is generally recognized to be the first to bridge the artificial gap between organic and inorganic chemistry, but it also showed the usefulness of heat in organic synthesis. Not only does an increase in temperature enhance the rate of urea synthesis, but Walker and Hambly showed that equilibrium between urea and ammonium cyanate was attainable and reversible at 100 C. Wohler's synthesis of urea, and subsequent syntheses of organic compounds from inorganic compounds over the next several decades dealt serious blows to the 'vital force' concept which held that: (1) organic compounds owe their formation to the action of a special force in living organisms; and (2) forces which determine the behavior of inorganic compounds play no part in living systems. Nevertheless, such progress was overshadowed by Pasteur's refutation of spontaneous generation which nearly extinguished experimental investigations into the origins of life for several decades. Vitalism was dealt a deadly blow in the 1950's with Miller's famous spark-discharge experiments which were undertaken in the framework of the Oparin and Haldane hypotheses concerning the origin of life. These hypotheses were constructed on some basic assumptions which included a reduced atmosphere, and a low surface temperature for the early Earth. These ideas meshed well with the prevailing hypothesis of the 1940's and 50's that the Earth had formed through heterogeneous accretion of dust from a condensing solar nebula. Miller's experiments were extremely successful, and were followed by numerous other experiments by various investigators who employed a wide variety of energy sources for abiotic synthesis including spark discharges, ultra-violet radiation, heat, shock waves, plasmas, gamma rays, and other forms of energy. The conclusion reached from this body of work is that energy inputs can drive organic synthesis from a variety of inorganic starting materials.

Shock, Everett L.

1992-01-01

42

Incorporation of Medicinal Chemistry into the Organic Chemistry Curriculum  

ERIC Educational Resources Information Center

Application of concepts presented in organic chemistry lecture using a virtual project involving the sythesis of medicinally important compounds is emphasized. The importance of reinforcing the concepts from lecture in lab, thus providing a powerful instructional means is discussed.

Forbes, David C.

2004-01-01

43

American Chemical Society: Division of Organic Chemistry  

NSDL National Science Digital Library

Established in 1908, the American Chemical Society (ACS) Organic Chemistry Division created this website to illustrate its work to cultivate and promote the advancement of the field of organic chemistry. Researchers can learn about upcoming meetings and conferences. Chemistry students and educators can learn about fellowship, awards, and employment opportunities. The website provides an extensive list of links to scientific journals. Visitors can also learn about membership benefits and how to join the group.

2006-01-24

44

5.13 Organic Chemistry II, Fall 2003  

E-print Network

Intermediate organic chemistry. Synthesis, structure determination, mechanism, and the relationships between structure and reactivity emphasized. Special topics in organic chemistry included to illustrate the role of organic ...

Jamison, Timothy F.

45

5.13 Organic Chemistry II, Spring 2003  

E-print Network

Intermediate organic chemistry. Synthesis, structure determination, mechanism, and the relationships between structure and reactivity emphasized. Special topics in organic chemistry included to illustrate the role of organic ...

Swager, Timothy Manning

46

Understanding Academic Performance in Organic Chemistry  

ERIC Educational Resources Information Center

Successful completion of organic chemistry is a prerequisite for many graduate and professional programs in science, technology, engineering, and mathematics, yet the failure rate for this sequence of courses is notoriously high. To date, few studies have examined why some students succeed while others have difficulty in organic chemistry. This…

Szu, Evan; Nandagopal, Kiruthiga; Shavelson, Richard J.; Lopez, Enrique J.; Penn, John H.; Scharberg, Maureen; Hill, Geannine W.

2011-01-01

47

Mechanochemical Synthesis of Two Polymorphs of the Tetrathiafulvalene-Chloranil Charge Transfer Salt: An Experiment for Organic Chemistry  

ERIC Educational Resources Information Center

Mechanochemical syntheses avoid or considerably reduce the use of reaction solvents, thus providing green chemistry synthetic alternatives that are both environmentally friendly and economically advantageous. The increased solid-state reactivity generated by mechanical energy imparted to the reactants by grinding or milling can offer alternative…

Wixtrom, Alex; Buhler, Jessica; Abdel-Fattah, Tarek

2014-01-01

48

Synthesis of Aspirin: A General Chemistry Experiment  

NASA Astrophysics Data System (ADS)

An experiment is described that is suitable for the early portion of the laboratory in a general chemistry course and integrates organic examples. It is the two-step synthesis of aspirin starting from oil of wintergreen. The mechanism for this synthesis provides examples of three major classes of chemical reactions: hydrolysis, condensation, and proton transfer. To understand the chemistry, the student must be able to recognize the common molecular framework shared by oil of wintergreen, salicylic acid, and aspirin and to identify the -OH and -CO2 sites where chemical changes occur. The experiment differs in three ways from traditional aspirin synthesis experiments for general chemistry. It is designed to be performed early rather than late; it starts from a naturally occurring material and requires two steps rather than one; and it utilizes FTIR spectroscopy to distinguish among oil of wintergreen starting material, salicylic acid intermediate, and aspirin product. The use of FTIR spectroscopy introduces students to a modern analytical technique that is currently used in research involving aspirin.

Olmsted, John A., III

1998-10-01

49

Chemistry of secondary organic aerosol formation  

NASA Astrophysics Data System (ADS)

The photooxidation of volatile organic compounds (VOCs) in the atmosphere can lead to the formation of secondary organic aerosol (SOA), a major component of fine particulate matter. Improvements to air quality require insight into the many reactive intermediates that lead to SOA formation, of which only a small fraction have been measured at the molecular level. This thesis describes the chemistry of secondary organic aerosol (SOA) formation from several atmospherically relevant hydrocarbon precursors. Photooxidation experiments of methoxyphenol and phenolic compounds and C12 alkanes were conducted in the Caltech Environmental Chamber. These experiments include the first photooxidation studies of these precursors run under sufficiently low NOx levels, such that RO2 + HO2 chemistry dominates, an important chemical regime in the atmosphere. Using online Chemical Ionization Mass Spectrometery (CIMS), key gas-phase intermediates that lead to SOA formation in these systems were identified. With complementary particle-phase analyses, chemical mechanisms elucidating the SOA formation from these compounds are proposed. Three methoxyphenol species (phenol, guaiacol, and syringol) were studied to model potential photooxidation schemes of biomass burning intermediates. SOA yields (ratio of mass of SOA formed to mass of primary organic reacted) exceeding 25% are observed. Aerosol growth is rapid and linear with the organic conversion, consistent with the formation of essentially non-volatile products. Gas and aerosol-phase oxidation products from the guaiacol system show that the chemical mechanism consists of highly oxidized aromatic species in the particle phase. Syringol SOA yields are lower than that of phenol and guaiacol, likely due to unique chemistry dependent on methoxy group position. The photooxidation of several C12 alkanes of varying structure n-dodecane, 2-methylundecane, cyclododecane, and hexylcyclohexane) were run under extended OH exposure to investigate the effect of molecular structure on SOA yields and photochemical aging. Peroxyhemiacetal formation from the reactions of several multifunctional hydroperoxides and aldehyde intermediates was found to be central to organic growth in all systems, and SOA yields increased with cyclic character of the starting hydrocarbon. All of these studies provide direction for future experiments and modeling in order to lessen outstanding discrepancies between predicted and measured SOA.

Yee, Lindsay Diana

50

Organic Chemistry 51B -Winter 2013 Organic Chemistry Peer Tutoring Program Chemistry 51B Reactions List  

E-print Network

° alkyl halide 4. Preparation of epoxides (Intramolecular SN2 reaction) #12;Organic Chemistry 51B - Winter attack via SN2 mechanism Reactions of Alcohols 1. Dehydration to form alkenes a. Using strong acid Can may occur) For 1° and methyl alcohols, mechanism is SN2 3. Reaction with other reagents to form RX

Rose, Michael R.

51

A Discovery Chemistry Experiment on Buffers  

ERIC Educational Resources Information Center

The Holy Cross Chemistry Department has designed and implemented an experiment on buffers as part of our Discovery Chemistry curriculum. The pedagogical philosophy of Discovery Chemistry is to make the laboratory the focal point of learning for students in their first two years of undergraduate instruction. We first pose questions in prelaboratory…

Kulevich, Suzanne E.; Herrick, Richard S.; Mills, Kenneth V.

2014-01-01

52

Green chemistry oriented organic synthesis in water.  

PubMed

The use of water as solvent features many benefits such as improving reactivities and selectivities, simplifying the workup procedures, enabling the recycling of the catalyst and allowing mild reaction conditions and protecting-group free synthesis in addition to being benign itself. In addition, exploring organic chemistry in water can lead to uncommon reactivities and selectivities complementing the organic chemists' synthetic toolbox in organic solvents. Studying chemistry in water also allows insight to be gained into Nature's way of chemical synthesis. However, using water as solvent is not always green. This tutorial review briefly discusses organic synthesis in water with a Green Chemistry perspective. PMID:22048162

Simon, Marc-Olivier; Li, Chao-Jun

2012-02-21

53

Statistical Automatic Summarization in Organic Chemistry  

Microsoft Academic Search

We present an oriented numerical summarizer algorithm, applied to producing automatic summaries of scientific documents in Organic Chemistry. We present its implementation named Yachs (Yet Another Chemistry Summarizer) that combines a specific document pre-processing with a sentence scoring method relying on the statistical properties of documents. We show that Yachs achieves the best results among several other summarizers on a

Florian Boudin; Patricia Velazquez-Morales; Juan Manuel Torres Moreno

2009-01-01

54

Implementing Temporary Facilities for Organic Chemistry Laboratory  

Microsoft Academic Search

Our classroom and laboratory facilities were recently remodeled, which required that we vacate our chemistry building temporarily. Construction was completed within 17 months with minimal interruption of class schedules, although some rather creative laboratory arrangements were necessary. My primary objective was to maintain our organic chemistry curriculum. Keys to success included support from the administration and other science faculty, and

Judith C. Amburgey-Peters

2002-01-01

55

Preparation, Characterization, and Postsynthetic Modification of Metal-Organic Frameworks: Synthetic Experiments for an Undergraduate Laboratory Course in Inorganic Chemistry  

ERIC Educational Resources Information Center

Metal-organic frameworks (MOFs) are crystalline materials that are composed of an infinite array of metal nodes (single ions or clusters) linked to one another by polyfunctional organic compounds. Because of their extraordinary surface areas and high degree of control over the physical and chemical properties, these materials have received much…

Sumida, Kenji; Arnold, John

2011-01-01

56

Acid-Catalyzed Preparation of Biodiesel from Waste Vegetable Oil: An Experiment for the Undergraduate Organic Chemistry Laboratory  

ERIC Educational Resources Information Center

This undergraduate organic laboratory exercise involves the sulfuric acid-catalyzed conversion of waste vegetable oil into biodiesel. The acid-catalyzed method, although inherently slower than the base-catalyzed methods, does not suffer from the loss of product or the creation of emulsion producing soap that plagues the base-catalyzed methods when…

Bladt, Don; Murray, Steve; Gitch, Brittany; Trout, Haylee; Liberko, Charles

2011-01-01

57

Analysis of Bromination of Ethylbenzene Using a 45 MHz NMR Spectrometer: An Undergraduate Organic Chemistry Laboratory Experiment  

ERIC Educational Resources Information Center

A 45 MHz benchtop NMR spectrometer is used to identify the structures and determine the amount of 1-bromoethylbenzene and 1,1-dibromoethylbenzene produced from free-radical bromination of ethylbenzene. The experiment is designed for nonchemistry majors, specifically B.S. Biology students, in a predominantly undergraduate institution with…

Isaac-Lam, Meden F.

2014-01-01

58

Preparation of a N-Heterocyclic Carbene Nickel(II) Complex: Synthetic Experiments in Current Organic and Organometallic Chemistry  

ERIC Educational Resources Information Center

A four-part experiment that leads to the synthesis of a cyclopentadienyl chloro-nickel(II) complex bearing a N-heterocyclic carbene (NHC) ligand is presented. In the first part, the preparation of 1,3-bis-(2,4,6-trimethylphenyl)imidazolium chloride (IMes[middle dot]HCl) in a one-pot procedure by reaction of 2,4,6-trimethylaniline with…

Ritleng, Vincent; Brenner, Eric; Chetcuti, Michael J.

2008-01-01

59

Cooperative Chemistry: Concept Mapping in the Organic Chemistry Lab.  

ERIC Educational Resources Information Center

Integrates concept mapping into the chemistry laboratory and requires students to construct a concept map for each experiment. Reports a decrease in student questions concerning set up and procedure. Recommends using computer software such as Chem Sketch 5.0 which is free and available from the Internet. (Contains 15 references.) (YDS)

Gahr, Allan A.

2003-01-01

60

Statistical Automatic Summarization in Organic Chemistry  

Microsoft Academic Search

We present an oriented numerical summarizer algorithm, applied to producing\\u000aautomatic summaries of scientific documents in Organic Chemistry. We present\\u000aits implementation named Yachs (Yet Another Chemistry Summarizer) that combines\\u000aa specific document pre-processing with a sentence scoring method relying on\\u000athe statistical properties of documents. We show that Yachs achieves the best\\u000aresults among several other summarizers on a

Florian Boudin; Patricia Velazquez-Morales; Juan-Manuel Torres-Moreno

2009-01-01

61

Nobel Chemistry in the Laboratory: Synthesis of a Ruthenium Catalyst for Ring-Closing Olefin Metathesis--An Experiment for the Advanced Inorganic or Organic Laboratory  

ERIC Educational Resources Information Center

An experiment for the upper-level undergraduate laboratory is described in which students synthesize a ruthenium olefin metathesis catalyst, then use the catalyst to carry out the ring-closing metathesis of diethyl diallylmalonate. The olefin metathesis reaction was the subject of the 2005 Nobel Prize in chemistry. The catalyst chosen for this…

Greco, George E.

2007-01-01

62

A Discovery-Based Experiment Involving Rearrangement in the Conversion of Alcohols to Alkyl Halides: Permanent Magnet [to the thirteenth power]C NMR in the First-Semester Organic Chemistry Lab  

ERIC Educational Resources Information Center

The use of permanent magnet [to the thirteenth power]C NMR in large-section first-semester organic chemistry lab courses is limited by the availability of experiments that not only hinge on first-semester lecture topics, but which also produce at least 0.5 mL of neat liquid sample. This article reports a discovery-based experiment that meets both…

Kjonaas, Richard A.; Tucker, Ryand J. F.

2008-01-01

63

Implementing Temporary Facilities for Organic Chemistry Laboratory  

NASA Astrophysics Data System (ADS)

Our classroom and laboratory facilities were recently remodeled, which required that we vacate our chemistry building temporarily. Construction was completed within 17 months with minimal interruption of class schedules, although some rather creative laboratory arrangements were necessary. My primary objective was to maintain our organic chemistry curriculum. Keys to success included support from the administration and other science faculty, and extensive planning. During the renovations, our organic chemistry laboratory was held in a 23 x 30-ft room normally used for a general physics laboratory. The major considerations for setting up a functional organic laboratory under these conditions were proper fume control (ductless fume enclosures), electrical needs, water supply, and safety issues. As described in this report, we were able to conduct a normal laboratory curriculum successfully.

Amburgey-Peters, Judith C.

2002-05-01

64

An Efficient Statistical Approach for Automatic Organic Chemistry Summarization  

E-print Network

of Organic Chemistry articles. 1 Introduction Over 1.7 million new Chemistry articles were published in 20071An Efficient Statistical Approach for Automatic Organic Chemistry Summarization Florian Boudin1 for summa- rizing scientific documents in Organic Chemistry that concentrates on numerical treatments. We

Avignon et des Pays de Vaucluse, Université de

65

Medical Mycology and the Chemistry Classroom: Germinating Student Interest in Organic Chemistry  

ERIC Educational Resources Information Center

Efforts to provide active research context to introductory courses in basic sciences are likely to better engage learners and provide a framework for relevant concepts. A simple teaching and learning experiment was conducted to use concepts in organic chemistry to solve problems in the life sciences. Bryant University is a liberal arts university…

Bliss, Joseph M.; Reid, Christopher W.

2013-01-01

66

Synthesis of Diels—Alder Adducts of Phencyclone and NMR Studies of Hindered Rotations of Unsubstituted Bridgehead Phenyls: Microscale Experiments in Organic Chemistry  

Microsoft Academic Search

Synthesis of Diels—Alder adducts of phencyclone with diverse dienophiles provides the basis for a major extended module in the second-semester laboratory of an organic chemistry course. With many accessible target compounds, students can have individual novel compounds to prepare. Especially attractive for students, the adducts are highly hindered, resulting in slow rotation about the C—C sp2—sp3 single bond to the

RONALD CALLAHAN; KEVIN BYNUM; RON PRIP; ROBERT ROTHCHILD

1998-01-01

67

Ethical Issues in Organic Chemistry.  

ERIC Educational Resources Information Center

Suggests that a literature survey can alert students to real-life ethical problems surrounding many organic compounds. Topic areas students could explore include: hazards in the workplace, toxic chemicals, and nerve gas structures. Background information and an extensive bibliography are given. (DH)

Coad, Peter; Coad, Raylene

1985-01-01

68

Organic composition of PM 2.5 and size-segregated aerosols and their sources during the 2002 Bay Regional Atmospheric Chemistry Experiment (BRACE), Florida, USA  

NASA Astrophysics Data System (ADS)

PM 2.5 and size-segregated aerosols were collected in May 2002 as part of the Bay Regional Atmospheric Chemistry Experiment (BRACE), Florida, USA. Aerosol organic composition was used to estimate sources of a series of alkanes and polycyclic aromatic hydrocarbons (PAHs) using chemical indices, hierarchical cluster analysis (HCA) and a chemical mass balance receptor model (CMB). Aerosols were collected on quartz fiber filters (QFF) using a PM 2.5 high volume sampler and on aluminum foil discs using a Micro-Orifice Uniform Deposit Impactor (MOUDI, 50% aerodynamic cut diameters were 18, 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.315 and 0.171 ?m). Target compounds included alkanes and PAHs and were solvent extracted using a mixture of dichloromethane, acetone and hexane, concentrated and then analyzed using a gas chromatograph/mass spectrometer (GC/MS). The target compounds in PM 2.5 were dominated by six sources during the study period: mobile sources (39±5%), coal burning (33±5%), biogenic primary emission (20±2%), oil combustion (5±2%), biomass burning (1.0±0.3%) and an unidentified source (3±2%). Results obtained from the chemical indices, HCA and CMB were in very good agreement with each other. PAH size distributions are presented for days dominated by a same source. Seventy-five percent and 50% of the PAH were found below 1.8 and 0.56 ?m, respectively (monthly PAH geometric diameters averaged 0.43 ?m). Coarse size PAHs were observed on 1 day (15 May) and were correlated with nitrate and sodium size distribution. It is hypothesized that the PAHs, sodium and nitrate were internally mixed and that the PAHs deposited onto a pre-existing marine aerosol. This transfer process has significant implications for PAH deposition and lifetime and warrants further study.

Tremblay, Raphaël T.; Riemer, Daniel D.; Zika, Rod G.

69

University of California Organic Chemistry Lab  

E-print Network

for students blind, visually impaired or have a learning disability) i. Internet Explorer 9 & 10 and Firefox and Conversations to Communicate in Your Course How to Check Your Grade Organic Chemistry Laboratory is hybrid, by Steven F. Pedersen, Jesse H. Pedersen. (ISBN: 9781111428167) Textbook is available from: Cal Student

Jacobs, Lucia

70

University of California Organic Chemistry Lab  

E-print Network

for students blind, visually impaired or have a learning disability) i. Internet Explorer 9 & 10 and Firefox, Discussions and Conversations to Communicate in Your Course How to Check Your Grade Organic Chemistry from: Cal Student Store 2. Computer Requirements Internet i. High-speed Internet ii. Minimum of 512kbps

Walker, Matthew P.

71

Measuring Conceptual Change in Organic Chemistry.  

ERIC Educational Resources Information Center

Describes a study that used the ordered-tree technique to investigate knowledge change across the first semester of a college course in organic chemistry. Finds that over the course of the semester, students' knowledge trees became more similar to those of their professors. Discusses possible assessment uses for the ordered-tree technique.…

Nash, Jane Gradwohl; Liotta, Louis J.; Bravaco, Ralph J.

2000-01-01

72

Experiments in the Chemistry of Food.  

ERIC Educational Resources Information Center

This booklet presents 18 experiments in the chemistry of food, suitable for elementary and secondary school science classes. Experiments deal with an analysis of milk, determinations of the amounts of sulfur dioxide, iron, and fat in foods, and the concentration of vitamin C in fruit juice and iodine in salt. Tests are provided for fats,…

Weaver, Elbert C.

73

Purdue University: Division of Organic Chemistry  

NSDL National Science Digital Library

Purdue University created this website to promote its organic chemistry department's diverse research initiatives. This expansive website provides links to materials on twelve of the faculty's chemistry research groups. Research includes NMR imaging of micellar solutions, hydride fuel cell examinations, dimerization inhibitors of transcription factors, and gas phase synthesis. Users can find lists of the many publications and view images and photos of the division's work and facilities. Visitors can learn about the many instruments used by the division such as mass spectrometry, continuously rotated cellular reactor, and an ozone generator.

74

Experiments for Modern Introductory Chemistry.  

ERIC Educational Resources Information Center

Presents a headspace gas chromatography experiment that enables discovery of the temperature dependence of the vapor pressure of a pure liquid. Illustrates liquid-vapor phase equilibrium of pure liquids. Contains 22 references. (JRH)

Kildahl, Nicholas; Berka, Ladislav H.

1995-01-01

75

Synthesis of Aspirin: A General Chemistry Experiment.  

ERIC Educational Resources Information Center

Describes the redesign of the first semester general chemistry laboratory at the college level. An organic component is included in the redesign and it provides students with explicit examples of several types of operations in which chemists engage. Contains 16 references. (DDR)

Olmsted, John III

1998-01-01

76

Teaching Introductory Organic Chemistry: 'Blooming' beyond a Simple Taxonomy  

NASA Astrophysics Data System (ADS)

Undergraduate students often experience fear and trepidation when studying introductory organic chemistry: the majority of these students use a memorization approach to the material, sacrificing understanding. This paper describes one way the problem can be resolved. The cognitive working level we emphasize in our teaching practice involves making the necessary connections between the general chemistry principles that students have learned (or at least have been exposed to in their senior high school years and have revisited again in their university freshman year) and the many reactions and mechanisms they will encounter in organic chemistry. Educating students early in the course about the various levels of the cognitive process and the necessary working level of cognition for success in organic chemistry teaches connections between the general chemistry principles and reaction mechanisms. This empowers students to approach the subject from a perspective of understanding rather than memorization, and replaces fear and trepidation with confidence. In addition, this can help narrow the gap between what instructors expect from their students and what their students think is sufficient to master the course content.

Pungente, Michael D.; Badger, Rodney A.

2003-07-01

77

Organic Chemistry Self Instructional Package 4: Alkanes-Nomenclature.  

ERIC Educational Resources Information Center

This booklet, one of a series of 17 developed at Prince George's Community College, Largo, Maryland, provides an individualized, self-paced undergraduate organic chemistry instruction module designed to augment any course in organic chemistry but particularly those taught using the text "Organic Chemistry" by Morrison and Boyd. The entire series…

Zdravkovich, V.

78

Organic Chemistry Self Instructional Package 5: Alkanes Preparations and Reactions.  

ERIC Educational Resources Information Center

This booklet, one of a series of 17 developed at Prince George's Community College, Largo, Maryland, provides an individualized, self-paced undergraduate organic chemistry instruction module designed to augment any course in organic chemistry but particularly those taught using the text "Organic Chemistry" by Morrison and Boyd. The entire series…

Zdravkovich, V.

79

Organic Chemistry Self Instructional Package 9: Alkenes-Reactions 1.  

ERIC Educational Resources Information Center

This booklet, one of a series of 17 developed at Prince George's Community College, Largo, Maryland, provides an individualized, self-paced undergraduate organic chemistry instruction module designed to augment any course in organic chemistry but particularly those taught using the text "Organic Chemistry" by Morrison and Boyd. The entire series…

Zdravkovich, V.

80

Organic Chemistry Self Instructional Package 8: Alkenes-Preparations.  

ERIC Educational Resources Information Center

This booklet, one of a series of 17 developed at Prince George's Community College, Largo, Maryland, provides an individualized, self-paced undergraduate organic chemistry instruction module designed to augment any course in organic chemistry but particularly those taught using the text "Organic Chemistry" by Morrison and Boyd. The entire series…

Zdravkovich, V.

81

An Experiment in Forensic Chemistry: The Breathalyzer.  

ERIC Educational Resources Information Center

Describes a simple experiment done in a quantitative analysis course that illustrates the chemistry of the breath alcohol test. Discusses the development and use of the Breathalyzer. Outlines the experimental procedure, along with the appropriate calculations and discussion of the results. (TW)

Timmer, William C.

1986-01-01

82

Special Topics in Organic Chemistry 8833A Pulping and Bleaching Chemistry  

E-print Network

Special Topics in Organic Chemistry 8833A Pulping and Bleaching Chemistry Course Description: This course focuses on developing an understanding of the fundamental chemistry associated with pulping. The focus is on alkaline/NaSH pulping and ClO2, H2O2, O2/NaOH, O3 bleaching chemistry of chemical

Sherrill, David

83

Tufts University Department of Chemistry Changes to Organic Chemistry and Biochemistry courses effective Fall 2013  

E-print Network

Tufts University Department of Chemistry Changes to Organic Chemistry and Biochemistry courses in their studies at Tufts. These changes are designed to benefit Chemistry, ACS-Certified Chemistry, and Biochemistry majors as well as other students interested in studying biochemistry at Tufts, such as those

Kounaves, Samuel P.

84

Students' Perceptions and Learning Experiences of Tertiary Level Chemistry.  

ERIC Educational Resources Information Center

There is evidence to suggest that first-year chemistry learning experiences may discourage students from studying further chemistry courses. This paper reports on an investigation on the influence of first year learning experiences in two first year chemistry courses on students' chemistry enrollment choices. Students enrolled in first year…

Dalgety, Jacinta; Coll, Richard K.

85

The tropical forest and fire emissions experiment: Emission, chemistry, and transport of biogenic volatile organic compounds in the lower atmosphere over Amazonia  

NASA Astrophysics Data System (ADS)

Airborne and ground-based mixing ratio and flux measurements using eddy covariance (EC) and for the first time the mixed layer gradient (MLG) and mixed layer variance (MLV) techniques are used to assess the impact of isoprene and monoterpene emissions on atmospheric chemistry in the Amazon basin. Average noon isoprene (7.8 ± 2.3 mg/m2/h) and monoterpene fluxes (1.2 ± 0.5 mg/m2/h) compared well between ground and airborne measurements and are higher than fluxes estimated in this region during other seasons. The biogenic emission model, Model of Emissions of Gases and Aerosols from Nature (MEGAN), estimates fluxes that are within the model and measurement uncertainty and can describe the large observed variations associated with land-use change in the region north-west of Manaus. Isoprene and monoterpenes accounted for ˜75% of the total OH reactivity in this region and are important volatile organic compounds (VOCs) for modeling atmospheric chemistry in Amazonia. The presence of fair weather clouds (cumulus humilis) had an important impact on the vertical distribution and chemistry of VOCs through the planetary boundary layer (PBL), the cloud layer, and the free troposphere (FT). Entrainment velocities between 10:00 and 11:30 local time (LT) are calculated to be on the order of 8-10 cm/s. The ratio of methyl-vinyl-ketone (MVK) and methacrolein (MAC) (unique oxidation products of isoprene chemistry) with respect to isoprene showed a pronounced increase in the cloud layer due to entrainment and an increased oxidative capacity in broken cloud decks. A decrease of the ratio in the lower free troposphere suggests cloud venting through activated clouds. OH modeled in the planetary boundary layer using a photochemical box model is much lower than OH calculated from a mixed layer budget approach. An ambient reactive sesquiterpene mixing ratio of 1% of isoprene would be sufficient to explain most of this discrepancy. Increased OH production due to increased photolysis in the cloud layer balances the low OH values modeled for the planetary boundary layer. The intensity of segregation (Is) of isoprene and OH, defined as a relative reduction of the reaction rate constant due to incomplete mixing, is found to be significant: up to 39 ± 7% in the ˜800-m-deep cloud layer. The effective reaction rate between isoprene and OH can therefore vary significantly in certain parts of the lower atmosphere.

Karl, Thomas; Guenther, Alex; Yokelson, Robert J.; Greenberg, Jim; Potosnak, Mark; Blake, Donald R.; Artaxo, Paulo

2007-09-01

86

Form and Function: An Organic Chemistry Module. Teacher's Guide.  

ERIC Educational Resources Information Center

This teacher's guide is designed to provide science teachers with the necessary guidance and suggestions for teaching organic chemistry. In this book, the diverse field of organic chemistry modules is introduced. The material in this book can be integrated with the other modules in a sequence that helps students to see that chemistry is a unified…

Jarvis, Bruce; Mazzocchi, Paul; Hearle, Robert

87

Atmospheric Chemistry Experiment (ACE): Mission overview  

Microsoft Academic Search

SCISAT-1, also known as the Atmospheric Chemistry Experiment (ACE), is a Canadian satellite mission for remote sensing of the Earth's atmosphere. It was launched into low Earth circular orbit (altitude 650 km, inclination 74°) on 12 Aug. 2003. The primary ACE instrument is a high spectral resolution (0.02 cm-1) Fourier Transform Spectrometer (FTS) operating from 2.2 to 13.3 mum (750-4400

P. F. Bernath; C. T. McElroy; M. C. Abrams; C. D. Boone; M. Butler; C. Camy-Peyret; M. Carleer; C. Clerbaux; P.-F. Coheur; R. Colin; P. DeCola; M. DeMazière; J. R. Drummond; D. Dufour; W. F. J. Evans; H. Fast; D. Fussen; K. Gilbert; D. E. Jennings; E. J. Llewellyn; R. P. Lowe; E. Mahieu; J. C. McConnell; M. McHugh; S. D. McLeod; R. Michaud; C. Midwinter; R. Nassar; F. Nichitiu; C. Nowlan; C. P. Rinsland; Y. J. Rochon; N. Rowlands; K. Semeniuk; P. Simon; R. Skelton; J. J. Sloan; M.-A. Soucy; K. Strong; P. Tremblay; D. Turnbull; K. A. Walker; I. Walkty; D. A. Wardle; V. Wehrle; R. Zander; J. Zou

2005-01-01

88

Organic chemistry in the oceans of Titan  

NASA Astrophysics Data System (ADS)

On Titan, most of the organics present in the atmosphere must condense in the lower stratosphere and be solid near the surface, except methane, ethane, propane, propene and 1-butene which must be liquid and could form oceans containing large fractions of dissolved N2. Chemical evolution on Titan must have followed a way very different from the terrestrial one, involving physical chemical processes in a cryogenic apolar solvent mainly composed of CH4-C2H6-N2, in place of organic chemistry in water. Systematic study of the volumic mass and solubility of organics in such a cryogenic mixture of various compositions, at 94K, is presented, using thermodynamic modelling. The results suggest that the oceans of Titan could be free of any "icebergs" of organic compounds. These oceans could be very rich in dissolved organics, with relatively high concentrations, in the range 1 - 10-6M. In addition, the concentration of several of the organic solutes should be constant, buffered by a bottom layer of the corresponding compound in the solid phase.

Raulin, F.

89

Novel Aryne Chemistry in Organic Synthesis  

SciTech Connect

Arynes are among the most intensively studied systems in chemistry. However, many aspects of the chemistry of these reactive intermediates are not well understood yet and their use as reagents in synthetic organic chemistry has been somewhat limited, due to the harsh conditions needed to generate arynes and the often uncontrolled reactivity exhibited by these species. Recently, o-silylaryl triflates, which can generate the corresponding arynes under very mild reaction conditions, have been found very useful in organic synthesis. This thesis describes several novel and useful methodologies by employing arynes, which generate from o-silylaryl triflates, in organic synthesis. An efficient, reliable method for the N-arylation of amines, sulfonamides and carbamates, and the O-arylation of phenols and carboxylic acids is described in Chapter 1. Amines, sulfonamides, phenols, and carboxylic acids are good nucleophiles, which can react with arynes generated from a-silylaryl triflates to afford the corresponding N- and O-arylated products in very high yields. The regioselectivity of unsymmetrical arynes has also been studied. A lot of useful, functional groups can tolerate our reaction conditions. Carbazoles and dibenzofurans are important heteroaromatic compounds, which have a variety of biological activities. A variety of substituted carbazoles and dibenzofwans are readily prepared in good to excellent yields starting with the corresponding o-iodoanilines or o-iodophenols and o-silylaryl triflates by a treatment with CsF, followed by a Pd-catalyzed cyclization, which overall provides a one-pot, two-step process. By using this methodology, the carbazole alkaloid mukonine has been concisely synthesized in a very good yield. Insertion of an aryne into a {sigma}-bond between a nucleophile and an electrophile (Nu-E) should potentially be a very beneficial process from the standpoint of organic synthesis. A variety of substituted ketones and sulfoxides have been synthesized in good yields via the intermolecular C-N {sigma}-bond addition of amides and S-N {sigma}-bond addition of sulfinamides to arynes under mild reaction conditions. The indazole moiety is a frequently found subunit in drug substances with important biological activities. Indazole analogues have been readily synthesized under mild reaction conditions by the [3+2] cycloaddition of a variety of diazo compounds with o-silylaryl triflates in the presence of CsF or TBAF. Polycyclic aromatic and heteroaromatic hydrocarbons have been synthesized in high yields by two different processes involving the Pd-catalyzed annulation of arynes. Both processes appear to involve the catalytic, stepwise coupling of two very reactive substrates, an aryne and an organopalladium species, to generate excellent yields of cross-coupled products.

Zhijian Liu

2006-12-12

90

Benchmarking Problems Used in Second Year Level Organic Chemistry Instruction  

ERIC Educational Resources Information Center

Investigations of the problem types used in college-level general chemistry examinations have been reported in this Journal and were first reported in the "Journal of Chemical Education" in 1924. This study extends the findings from general chemistry to the problems of four college-level organic chemistry courses. Three problem typologies were…

Raker, Jeffrey R.; Towns, Marcy H.

2010-01-01

91

Atmospheric Prebiotic Chemistry and Organic Hazes  

NASA Technical Reports Server (NTRS)

Earth's atmospheric composition at the time of the origin of life is not known, but it has often been suggested that chemical transformation of reactive species in the atmosphere was a significant source of pre biotic organic molecules. Experimental and theoretical studies over the past half century have shown that atmospheric synthesis can yield molecules such as amino acids and nucleobases, but these processes are very sensitive to gas composition and energy source. Abiotic synthesis of organic molecules is more productive in reduced atmospheres, yet the primitive Earth may not have been as reducing as earlier workers assumed, and recent research has reflected this shift in thinking. This work provides a survey of the range of chemical products that can be produced given a set of atmospheric conditions, with a particular focus on recent reports. Intertwined with the discussion of atmospheric synthesis is the consideration of an organic haze layer, which has been suggested as a possible ultraviolet shield on the anoxic early Earth. Since such a haze layer - if formed - would serve as a reservoir for organic molecules, the chemical composition of the aerosol should be closely examined. The results highlighted here show that a variety of products can be formed in mildly reducing or even neutral atmospheres, demonstrating that contributions of atmospheric synthesis to the organic inventory on early Earth should not be discounted. This review intends to bridge current knowledge of the range of possible atmospheric conditions in the prebiotic environment and pathways for synthesis under such conditions by examining the possible products of organic chemistry in the early atmosphere.

Trainer, Melissa G.

2012-01-01

92

Distributed Pore Chemistry in Porous Organic Polymers  

NASA Technical Reports Server (NTRS)

A method for making a biocompatible polymer article using a uniform atomic oxygen treatment is disclosed. The sub-strate may be subsequently optionally grated with a compatibilizing compound. Compatibilizing compounds may include proteins, phosphorylcholine groups, platelet adhesion preventing polymers, albumin adhesion promoters, and the like. The compatibilized substrate may also have a living cell layer adhered thereto. The atomic oxygen is preferably produced by a flowing afterglow microwave discharge, wherein the substrate resides in a sidearm out of the plasma. Also, methods for culturing cells for various purposes using the various membranes are disclosed as well. Also disclosed are porous organic polymers having a distributed pore chemistry (DPC) comprising hydrophilic and hydrophobic region, and a method for making the DPC by exposing the polymer to atomic oxygen wherein the rate of hydrophilization is greater than the rate of mass loss.

Koontz, Steven L. (Inventor)

1998-01-01

93

Problem Types in Synthetic Organic Chemistry Research: Implications for the Development of Curricular Problems for Second-Year Level Organic Chemistry Instruction  

ERIC Educational Resources Information Center

Understanding of the nature of science is key to the development of new curricular materials that mirror the practice of science. Three problem types (project level, synthetic planning, and day-to-day) in synthetic organic chemistry emerged during a thematic content analysis of the research experiences of eight practising synthetic organic

Raker, Jeffrey R.; Towns, Marcy H.

2012-01-01

94

Form and Function: An Organic Chemistry Module.  

ERIC Educational Resources Information Center

This book is one in the series of Interdisciplinary Approaches to Chemistry (IAC) designed to help students discover that chemistry is a lively science and actively used to pursue solutions to the important problems of today. It is expected for students to see how chemistry takes place continuously all around and to readily understand the daily…

Jarvis, Bruce; Mazzocchi, Paul

95

Teaching Introductory Organic Chemistry: 'Blooming' beyond a Simple Taxonomy.  

ERIC Educational Resources Information Center

Suggests that most students approach organic chemistry classes with a certain amount of apprehension and try to just manage or memorize the material rather than understand it. Recommends the use of Bloom's taxonomy as a way to increase comprehension and gives an example of how to use it in an organic chemistry classroom. (SOE)

Pungente, Michael D.; Badger, Rodney A.

2003-01-01

96

The low temperature organic chemistry of Titan's geofluid.  

PubMed

Organic chemistry on Titan and prebiotic chemistry on Earth involve the same N-containing organics: nitriles and their oligomers. Couplings of their chemistry in the three parts of Titan's geofluid (atmosphere, aerosols and surface) seem to play a key role in the organic chemical evolution of the planet. If liquid water was present on Titan, then a prebiotic chemistry, involving eutectics, similar to that of the early Earth, may have occurred. However, liquid water is currently absent and a prebiotic chemistry based only on N-organics may be evolving now on Titan. The other consequence of the low temperatures of Titan is the possible formation of organics unstable at room temperature and very reactive. So far, these compounds have not been systematically searched for in experimental studies of Titan's organic chemistry. C4N2 has already been detected on Titan. Powerful reactants in organic chemistry, CH2N2, and CH3N3, may be also present. They exhibit spectral signatures in the mid-IR strong enough to allow their detection at the 10-100 ppb level. They may be detectable on future IR spectra (ISO and Cassini) of Titan. PMID:11539246

Raulin, F; Bruston, P; Paillous, P; Sternberg, R

1995-03-01

97

Teaching Lab Report Writing through Inquiry: A Green Chemistry Stoichiometry Experiment for General Chemistry  

ERIC Educational Resources Information Center

We present an alternative to a traditional first-year chemistry laboratory experiment. This experiment has four key features: students utilize stoichiometry, learn and apply principles of green chemistry, engage in authentic scientific inquiry, and discover why each part of a scientific lab report is necessary. The importance and essential…

Cacciatore, Kristen L.; Sevian, Hannah

2006-01-01

98

Synthetic biology: lessons from the history of synthetic organic chemistry  

E-print Network

Synthetic biology: lessons from the history of synthetic organic chemistry Brian J Yeh & Wendell Science Foundation Synthetic Biology Engineering Research Center. e-mail: lim@cmp.ucsf.edu J.Iwasa Synthetic approaches may transform biology just as they transformed chemistry. NATURE CHEMICAL BIOLOGY

Lim, Wendell

99

Integrating Pharmacology into the Organic Chemistry Course  

NSDL National Science Digital Library

Many nonchemistry majors are unaware of the unity between chemistry and biology and tend to separate the two disciplines conceptually. In a course designed to emphasize health-related issues using a pharmacological approach, students gained a much better

Kelley, Colleen; Gaither, Katy K.

2001-05-01

100

Photolysis of 4-Phenyl-1,3-dioxolan-2-one: An Undergraduate Experiment in Free Radical Chemistry.  

ERIC Educational Resources Information Center

Describes a photochemistry experiment designed to introduce photochemical techniques and experience free radical chemistry. Selects Nuclear Magnetic Resonance spectroscopy for the analysis. This activity is suggested for use in an upper level undergraduate organic course. (MVL)

White, Rick C.; Ma, Sha

1988-01-01

101

Development and Formative Evaluation of Computer Simulated College Chemistry Experiments.  

ERIC Educational Resources Information Center

This article describes the design, preparation, and initial evaluation of a set of computer-simulated chemistry experiments. The experiments entailed the use of an atomic emission spectroscope and a single-beam visible absorption spectrophometer. (Author/IRT)

Cavin, Claudia S.; Cavin, E. D.

1978-01-01

102

Quantum Dots: An Experiment for Physical or Materials Chemistry  

ERIC Educational Resources Information Center

An experiment is conducted for obtaining quantum dots for physical or materials chemistry. This experiment serves to both reinforce the basic concept of quantum confinement and providing a useful bridge between the molecular and solid-state world.

Winkler, L. D.; Arceo, J. F.; Hughes, W. C.; DeGraff, B. A.; Augustine, B. H.

2005-01-01

103

An Undergraduate Organic Chemistry Laboratory: The Facile Hydrogenation of Methyl Trans-Cinnamate  

ERIC Educational Resources Information Center

Hydrogenation of alkenes is an important reaction in the synthesis of organic molecules. In this experiment, students conduct a high-yield microscale hydrogenation reaction of methyl "trans"-cinnamate using a readily available, safe, and convenient hydrogen source. The conditions are similar to those seen in an organic chemistry textbook for an…

O'Connor, Kenneth J.; Zuspan, Kimberly; Berry, Lonnie

2011-01-01

104

Topic Sequence and Emphasis Variability of Selected Organic Chemistry Textbooks  

ERIC Educational Resources Information Center

Textbook choice has a significant effect upon course success. Among the factors that influence this decision, two of the most important are material organization and emphasis. This paper examines the sequencing of 19 organic chemistry topics, 21 concepts and skills, and 7 biological topics within nine of the currently available organic textbooks.…

Houseknecht, Justin B.

2010-01-01

105

A Template-Controlled Solid-State Reaction for the Organic Chemistry Laboratory  

ERIC Educational Resources Information Center

An experiment for the organic chemistry laboratory that involves a template-controlled solid-state reaction is described. The experiment utilizes a template to direct the assembly of an olefin in the solid state that undergoes a [2 + 2] photodimerization.

Friscic, Tomislav; Hamilton, Tamara D.; Papaefstathiou, Giannis S.; MacGillivray, Leonard R.

2005-01-01

106

Circular Dichroism Investigation of Dess-Martin Periodinane Oxidation in the Organic Chemistry Laboratory  

ERIC Educational Resources Information Center

Dess-Martin periodinane oxidation is an experiment that provides an avenue to the introduction of Circular Dichroism (CD) spectroscopy in organic chemistry curriculum as a diagnostic tool for examination of the results of a familiar reaction, and absolute configuration. From the experiment, students increased their understanding of CD theory and…

Reed, Nicole A.; Rapp, Robert D.; Hamann, Christian S.; Artz, Pamela G.

2005-01-01

107

Preparation of a D-Glucose-Derived Alkene. An E2 Reaction for the Undergraduate Organic Chemistry Laboratory  

Microsoft Academic Search

As the carbohydrates continue to gain attention for their central role in numerous areas of chemistry and biology, there is a growing need for experiments at the undergraduate level that highlight these fascinating compounds. In this article we describe a simple two-step laboratory experiment that may be used to highlight several important concepts introduced in sophomore organic chemistry, as applied

Peter Norris; Andrew Fluxe

2001-01-01

108

The Atmospheric Chemistry Experiment (ACE): Latest Results  

NASA Astrophysics Data System (ADS)

ACE (also known as SCISAT) is making a comprehensive set of simultaneous measurements of numerous trace gases, thin clouds, aerosols and temperature by solar occultation from a satellite in low earth orbit. A high inclination (74 degrees) low earth orbit (650 km) gives ACE coverage of tropical, mid-latitudes and polar regions. A high-resolution (0.02 cm-1) infrared Fourier Transform Spectrometer (FTS) operating from 2 to 13 microns (750-4400 cm-1) is measuring the vertical distribution of trace gases, and the meteorological variables of temperature and pressure. Aerosols and clouds are being monitored using the extinction of solar radiation at 0.525 and 1.02 microns as measured by two filtered imagers as well as by their infrared spectra. A dual spectrograph called MAESTRO extends the wavelength coverage to the 400-1000 nm spectral region. The principal investigator for MAESTRO is T. McElroy of the Meteorological Service of Canada. The FTS and imagers have been built by ABB-Bomem in Quebec City, while the satellite bus has been made by Bristol Aerospace in Winnipeg. ACE is part of the Canadian Space Agency's small satellite program, and was launched by NASA on 12 August 2003 for a nominal 2-year mission. The first results of ACE have been presented in a special issue of Geophysics Research Letters (http://www.agu.org/journals/ss/ACECHEM1/) in 2005 and recently a special issue on ACE validation has been prepared for Atmospheric Chemistry and Physics by K. Walker and K. Strong. A mission overview and status report will be presented. Science results for a few selected topics including the detection of organic molecules such as methanol and formaldehyde in the troposphere will be discussed.

Bernath, P.

2008-12-01

109

Infusing the Chemistry Curriculum with Green Chemistry Using Real-World Examples, Web Modules, and Atom Economy in Organic Chemistry Courses  

NASA Astrophysics Data System (ADS)

Green chemistry principles and practices have been infused in the chemistry curriculum at the University of Scranton, including courses in general, organic, and inorganic chemistry, biochemistry, environmental, polymer, industrial, and advanced organic chemistry, and chemical toxicology. Web-based green chemistry teaching modules have been developed for each of these courses. We describe the principles underlying green chemistry and methods of introducing these concepts into the curriculum with an example of incorporating green chemistry into the undergraduate lecture and laboratory organic sequence. See Featured Molecules .

Cann, Michael C.; Dickneider, Trudy A.

2004-07-01

110

Generation, Isolation, and Characterization of a Stable Enol from Grignard Addition to a Bis-Ester: A Microscale Experiment for the Undergraduate Organic Chemistry Laboratory  

ERIC Educational Resources Information Center

An experiment is described that introduces students to the concept of temperature-dependent stability of the tetrahedral intermediate in an acyl-transfer reaction. The process involves the determination of the structure of an alpha-ketoester and its corresponding remarkably stable enol ester to suggest a mechanism for the formation of the products.

Nicaise, Olivier J. C.; Ostrom, Kyle F.; Dalke, Brent J.

2005-01-01

111

Saying What You Mean: Teaching Mechanisms in Organic Chemistry  

ERIC Educational Resources Information Center

Organic reactions in introductory organic chemistry courses are most commonly taught with a mechanism-based approach to the understanding of molecular reactivity. However, the effectiveness of the popular curved arrow representation to describe reaction mechanisms is often compromised by the overuse of shortcuts and obscure notation. The…

Friesen, J. Brent

2008-01-01

112

An Efficient Statistical Approach for Automatic Organic Chemistry Summarization  

Microsoft Academic Search

In this paper, we propose an efficient strategy for summarizing scientific documents in Organic Chemistry that concentrates\\u000a on numerical treatments. We present its implementation named yachs (Yet Another Chemistry Summarizer) that combines a specific document pre-processing with a sentence scoring method relying\\u000a on the statistical properties of documents. We show that yachs achieves the best results among several other summarizers

Florian Boudin; Juan Manuel Torres Moreno; Patricia Velázquez-morales

2008-01-01

113

Using Microcomputers in the Physical Chemistry Laboratory: Activation Energy Experiment.  

ERIC Educational Resources Information Center

Describes a computer program, "Activation Energy," which is designed for use in physical chemistry classes and can be modified for kinetic experiments. Provides suggestions for instruction, sample program listings, and information on the availability of the program package. (ML)

Touvelle, Michele; Venugopalan, Mundiyath

1986-01-01

114

Theoretical advances toward understanding recent experiments in biophysical chemistry  

E-print Network

Several theoretical advances are presented, with the common theme of helping better understand and guide recent experiments in biophysical chemistry. In Chapter 2, I consider a recent criticism of the Jarzynski equality, ...

Zimanyi, Eric Norman

2012-01-01

115

View from My Classroom: Introductory Organic Chemistry with Instrumental Analysis: A Third Year High School Chemistry Course.  

ERIC Educational Resources Information Center

Describes an advanced high school chemistry course that exposes students to a wide variety of modern, realistic instrumental techniques. The laboratory syllabus for the course (which uses the textbook "Organic Chemistry" by Morrison and Boyd) is included. (JN)

Liebermann, John, Jr.

1985-01-01

116

Operational Amplifier Experiments for the Chemistry Laboratory.  

ERIC Educational Resources Information Center

Provides details of experiments that deal with the use of operational amplifiers and are part of a course in instrumental analysis. These experiments are performed after the completion of a set of electricity and electronics experiments. (DDR)

Braun, Robert D.

1996-01-01

117

The Big Picture; A Classroom Activity for Organic Chemistry  

NSDL National Science Digital Library

In the article "The Big Picture: A Classroom Activity for Organic Chemistry", Thomas Poon makes interesting use of the device exploited by Istvan Banyai in his Zoom books to help students of organic chemistry make connections between the molecular world and ways in which those molecules are important in daily life. The paper should have appeal at all levels of science education from the time the idea of molecules is first introduced through college-level courses. Along the way, students will encounter important biological molecules (such as chlorophyll), inks (such as pen ink), CFCs, hydrocarbon fuels, plastics (such as Lexan polycarbonate), and molecules with medical applications (such as aspirin and novocaine).

118

Tautomerization of Acetylacetone Enol. A Physical Organic Experiment in Kinetics and Thermodynamics.  

ERIC Educational Resources Information Center

Describes a physical organic experiment in thermodynamics and kinetics for undergraduate courses in organic chemistry, biochemistry, or physical chemistry. Details background information, solution preparations, equipment and methods, and the suggested experiments such as determination of general-base-catalytic coefficients and the Bronsted…

Spyridis, Greg T.; Meany, J. E.

1988-01-01

119

Chemistry of Organic Electronic Materials 6483-Fall  

E-print Network

. Example of a flexible organic light-emitting diode (OLED) (from the Center to their electrical properties and optical absorption Electrically conducting polymers Basic concepts of conductivity Introduction to the concepts of polarons

Sherrill, David

120

Green Oxidation of Menthol Enantiomers and Analysis by Circular Dichroism Spectroscopy: An Advanced Organic Chemistry Laboratory  

ERIC Educational Resources Information Center

Green chemistry addresses environmental concerns associated with chemical processes and increases awareness of possible harmful effects of chemical reagents. Efficient reactions that eliminate or reduce the use of organic solvents or toxic reagents are increasingly available. A two-week experiment is reported that entails the calcium hypochlorite…

Geiger, H. Cristina; Donohoe, James S.

2012-01-01

121

Structure Determination of Unknown Organic Liquids Using NMR and IR Spectroscopy: A General Chemistry Laboratory  

ERIC Educational Resources Information Center

This experiment introduced general chemistry students to the basic concepts of organic structures and to the power of spectroscopic methods for structure determination. Students employed a combination of IR and NMR spectroscopy to perform de novo structure determination of unknown alcohols, without being provided with a list of possible…

Pavel, John T.; Hyde, Erin C.; Bruch, Martha D.

2012-01-01

122

A Green, Guided-Inquiry Based Electrophilic Aromatic Substitution for the Organic Chemistry Laboratory  

ERIC Educational Resources Information Center

We developed an alternative electrophilic aromatic substitution reaction for the organic chemistry teaching laboratory. The experiment is an electrophilic iodination reaction of salicylamide, a popular analgesic, using environmentally friendly reagents--sodium iodide and household bleach. Further, we designed the lab as a guided-inquiry…

Eby, Eric; Deal, S. Todd

2008-01-01

123

Oxidation and Reduction Reactions in Organic Chemistry  

ERIC Educational Resources Information Center

A variety of approaches to the concept of oxidation and reduction appear in organic textbooks. The method proposed here is different than most published approaches. The oxidation state is calculated by totaling the number of heterogeneous atoms, [pi]-bonds, and rings. A comparison of the oxidation states of reactant and product determine what type…

Shibley, Ivan A., Jr.; Amaral, Katie E.; Aurentz, David J.; McCaully, Ronald J.

2010-01-01

124

Ideal Gas Laws: Experiments for General Chemistry  

ERIC Educational Resources Information Center

Describes a series of experiments designed to verify the various relationships implicit in the ideal gas equation and shows that the success of the Graham's law effusion experiments can be explained by elementary hydrodynamics. (GS)

Deal, Walter J.

1975-01-01

125

Two Multipurpose Thermochemical Experiments for General Chemistry.  

ERIC Educational Resources Information Center

Describes two experiments designed to provide concepts on the difference between heat and temperature and also bond energy. Investigates both a neutralization experiment and a ligation experiment. Notes inexpensive chemicals are used along with simple equipment. Discusses the sharing of lab results for a single class value. (MVL)

Wentworth, R. A. D.

1988-01-01

126

Patterns in Organometallic Chemistry with Application in Organic Synthesis.  

ERIC Educational Resources Information Center

Of interest in this discussion of organometallic complexes are stoichiometric or catalytic reagents for organic synthesis in the complex transformations observed during synthesis for transition metal organometallic complexes. Detailed are general reaction types from which the chemistry or many transition metal organometallic complexes can be…

Schwartz, Jeffrey; Labinger, Jay A.

1980-01-01

127

Lesson Planner for Demonstrations in Organic Chemistry Videodisc  

Microsoft Academic Search

Lesson Planner is a Microsoft Excel (1) macro that generates barcodes for video included on the Demonstrations in Organic Chemistry videodisc (2). It allows instructors who do not have computer control capability for their videodisc player, but do have a barcode reader, to prepare customized lessons for use in the classroom or laboratory. There is no need to flip through

Todd A. Surovell

1995-01-01

128

Non-Mathematical Problem Solving in Organic Chemistry  

ERIC Educational Resources Information Center

Differences in problem-solving ability among organic chemistry graduate students and faculty were studied within the domain of problems that involved the determination of the structure of a molecule from the molecular formula of the compound and a combination of IR and [to the first power]H NMR spectra. The participants' performance on these tasks…

Cartrette, David P.; Bodner, George M.

2010-01-01

129

OrganicPad: a tablet PC based chemistry tool  

Microsoft Academic Search

This paper describes a software tool that provides a natural user interface through the use of a Tablet PC for organic chemistry. The use of Tablet PCs is spreading throughout the computer world. Proof of this is from increased submission count at ACM SIGCSE and IEEE FIE and new conferences such as WIPTE 2007 (Workshop on the Impact of Pen

Sam Bryfczynski

2008-01-01

130

Solventless and One-Pot Synthesis of Cu(II) Phthalocyanine Complex: A Green Chemistry Experiment  

ERIC Educational Resources Information Center

With the growing awareness of green chemistry, it is increasingly important for students to understand this concept in the context of laboratory experiments. Although microwave-assisted organic synthesis has become a common and invaluable technique in recent years, there have been few procedures published for microwave-assisted inorganic synthesis…

Sharma, R. K.; Sharma, Chetna; Sidhwani, Indu Tucker

2011-01-01

131

Spectroelectrochemical Sensing of Aqueous Iron: An Experiment for Analytical Chemistry  

ERIC Educational Resources Information Center

We have designed a laboratory experiment to illustrate the use of spectroelectrochemical techniques for determination of aqueous iron. The experiment described in this article is applicable to an undergraduate laboratory course in analytical chemistry. Students are asked to fabricate spectroelectrochemical sensors, make electrochemical and optical…

Shtoyko, Tanya; Stuart, Dean; Gray, H. Neil

2007-01-01

132

A General Chemistry Experiment Incorporating Synthesis and Structural Determination  

Microsoft Academic Search

An experiment for the general chemistry laboratory is described wherein gas chromatography-mass spectroscopy (GC-MS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) are used to characterize the products of a series of microscale reactions on vanillin. A single sophisticated instrument can be incorporated into the laboratory given sufficient attention to the use of sampling accessories and software macros. Synthetic experiments

Hal van Ryswyk

1997-01-01

133

Some Experiments in Sulfur-Nitrogen Chemistry.  

ERIC Educational Resources Information Center

Briefly surveys the main structural types of sulfur-nitrogen compounds, and describes syntheses, suitable as undergraduate experiments, which illustrate four of the five types of cyclic species. Laboratory procedures, background information, and discussion of results for these experiments are provided. (Author/JN)

Banister, Arthur J.; Smith, Nigel R. M.

1982-01-01

134

Solar Energy Experiment for Beginning Chemistry.  

ERIC Educational Resources Information Center

Describes an experiment illustrating how such chemical concepts as light absorption, thermodynamics, and solid-state photovoltaics can be incorporated into solar energy education. Completed in a three-hour period, the experiment requires about two hours for data collections with the remaining hour devoted to calculations and comparison of results.…

Davis, Clyde E.

1983-01-01

135

Statistical Analysis Experiment for Freshman Chemistry Lab.  

ERIC Educational Resources Information Center

Describes a laboratory experiment dissolving zinc from galvanized nails in which data can be gathered very quickly for statistical analysis. The data have sufficient significant figures and the experiment yields a nice distribution of random errors. Freshman students can gain an appreciation of the relationships between random error, number of…

Salzsieder, John C.

1995-01-01

136

The Atmospheric Chemistry Experiment (ACE): Mission Overview  

NASA Astrophysics Data System (ADS)

The ACE mission goals are: (1) to measure and to understand the chemical and dynamical processes that control the distribution of ozone in the upper troposphere and stratosphere, with a particular emphasis on the Arctic region; (2) to explore the relationship between atmospheric chemistry and climate change; (3) to study the effects of biomass burning in the free troposphere; (4) to measure aerosol number density, size distribution and composition in order to reduce the uncertainties in their effects on the global energy balance. ACE will make a comprehensive set of simultaneous measurements of trace gases, thin clouds, aerosols, and temperature by solar occultation from a satellite in low earth orbit. A high inclination (74 degrees) low earth orbit (650 km) will give ACE coverage of tropical, mid-latitudes and polar regions. The solar occultation advantages are high sensitivity and self-calibration. A high-resolution (0.02 cm-1) infrared Fourier Transform Spectrometer (FTS) operating from 2 to 13 microns (750-4100 cm-1) will measure the vertical distribution of trace gases, and the meteorological variables of temperature and pressure. The ACE concept is derived from the now-retired ATMOS FTS instrument, which flew on the Space Shuttle in 1985, 1992, 1993, 1994. Climate-chemistry coupling may lead to the formation of an Arctic ozone hole. ACE will provide high quality data to confront these model predictions and will monitor polar chemistry as chlorine levels decline. The ACE-FTS can measure water vapor and HDO in the tropical tropopause region to study dehydration and strat-trop exchange. The molecular signatures of massive forest fires will evident in the ACE infrared spectra. The CO_2 in our spectra can be used to either retrieve atmospheric pressure or (if the instrument pointing knowledge proves to be satisfactory) for an independent retrieval of a CO_2 profile for carbon cycle science. Aerosols and clouds will be monitored using the extinction of solar radiation at 0.525 and 1.02 microns as measured by two filtered imagers as well as by their infrared spectra. A dual spectrograph called MAESTRO has been added to the mission to extend the wavelength coverage to the 280-1000 nm spectral region. The broad-band atmospheric extinction measured with high signal-to-noise ratio by MAESTRO is particularly useful for the derivation of aerosol and cloud physical properties. The PI for the MAESTRO instrument is T. McElroy from the Meteorological Service of Canada. ACE is unique in that MAESTRO, the ACE-FTS and the imagers all share the same suntracker and make simultaneous measurements of the same scene. The FTS and imagers have been built by ABB-Bomem in Quebec City, while the satellite bus has been made by Bristol Aerospace in Winnipeg. ACE has been selected in the Canadian Space Agency's SCISAT-1 program for a planned launch by NASA in May 2003 for a 2 year mission. The main international partners for ACE are NASA, for the launch and algorithm work at NASA-Langley, and Belgium/ESA, for the CMOS imaging arrays and scientific support.

Bernath, P.

2003-04-01

137

The Atmospheric Chemistry Experiment (ACE): Mission Overview  

NASA Astrophysics Data System (ADS)

The ACE mission goals are: (1) to measure and to understand the chemical and dynamical processes that control the distribution of ozone in the upper troposphere and stratosphere, with a particular emphasis on the Arctic region; (2) to explore the relationship between atmospheric chemistry and climate change; (3) to study the effects of biomass burning in the free troposphere; (4) to measure aerosol number density, size distribution and composition in order to reduce the uncertainties in their effects on the global energy balance. ACE will make a comprehensive set of simultaneous measurements of trace gases, thin clouds, aerosols, and temperature by solar occultation from a satellite in low earth orbit. A high inclination (74 degrees) low earth orbit (650 km) gives ACE coverage of tropical, mid-latitudes and polar regions. The solar occultation advantages are high sensitivity and self-calibration. A high-resolution (0.02 cm-1) infrared Fourier Transform Spectrometer (FTS) operating from 2 to 13 microns (750-4100 cm-1) will measure the vertical distribution of trace gases, and the meteorological variables of temperature and pressure. The ACE concept is derived from the now-retired ATMOS FTS instrument, which flew on the Space Shuttle in 1985, 1992, 1993, 1994. Climate-chemistry coupling may lead to the formation of an Arctic ozone hole. ACE will provide high quality data to confront these model predictions and will monitor polar chemistry as chlorine levels decline. The ACE-FTS can measure water vapor and HDO in the tropical tropopause region to study dehydration and strat-trop exchange. The molecular signatures of massive forest fires will evident in the ACE infrared spectra. The CO2 in our spectra can be used to either retrieve atmospheric pressure or (if the instrument pointing knowledge proves to be satisfactory) for an independent retrieval of a CO2 profile for carbon cycle science. Aerosols and clouds will be monitored using the extinction of solar radiation at 0.525 and 1.02 microns as measured by two filtered imagers as well as by their infrared spectra. A dual spectrograph called MAESTRO has been added to the mission to extend the wavelength coverage to the 280-1000 nm spectral region. The broad-band atmospheric extinction measured with high signal-to-noise ratio by MAESTRO is particularly useful for the derivation of aerosol and cloud physical properties. The PI for the MAESTRO instrument is T. McElroy from the Meteorological Service of Canada (MSC). ACE is unique in that MAESTRO, the ACE-FTS and the imagers all share the same suntracker and make simultaneous measurements of the same scene. The FTS and imagers have been built by ABB-Bomem in Quebec City, while the satellite bus has been made by Bristol Aerospace in Winnipeg. ACE was selected in the Canadian Space Agency's SCISAT-1 program, and was successfully launched by NASA on August 12, 2003 for a 2 year mission. The main international partners for ACE are NASA, for the launch and algorithm work at NASA-Langley, and Belgium/ESA, for the CMOS imaging arrays and scientific support.

Bernath, P. F.; Boone, C.; Walker, K.; McLeod, S.; Nassar, R.

2003-12-01

138

Cooperative Chemistry  

NSDL National Science Digital Library

Concept mapping in the organic chemistry laboratory can supplant cookbook activities with higher cognitive exercises. The common thread of most organic lab experiments is the synthesis, isolation, purification, and characterization of a carbon compound. T

Gahr, Allan A.

2003-02-01

139

Chemistry Notes.  

ERIC Educational Resources Information Center

Describes 13 activities, experiments and demonstrations, including the preparation of iron (III) chloride, simple alpha-helix model, investigating camping gas, redox reactions of some organic compounds, a liquid crystal thermometer, and the oxidation number concept in organic chemistry. (JN)

School Science Review, 1981

1981-01-01

140

New organic chemistry of sulfur dioxide.  

PubMed

Simple 1,3-dienes undergo highly stereoselective hetero-Diels-Alder additions with SO2 at low temperature giving sultines. These reactions that are faster than the more exothermic cheletropic additions of SO2-producing sulfolenes. This has led to the invention of a new C-C bond-forming reaction combining electron-rich dienes and alkenes with SO2. The reaction cascade has been exploited to develop combinatorial, one-pot, four-component syntheses of polyfunctional sulfones, sulfonamides, and sulfonic esters. It also allows us to generate, in one-pot operations, enantiomerically enriched polypropionate fragments containing up to three contiguous stereogenic centers and a (E)-alkene unit. These fragments can be used directly in further C-C bond-forming reactions, such as cross-aldol condensations, thus permitting the expeditious construction of complicated natural products of biological interest (e.g., Baconipyrones, Rifamycin S, Apoptolidinone) and analogues. New ene reactions of SO2 have also been discovered; they open new avenues to organic synthesis. PMID:17685582

Vogel, Pierre; Turks, Maris; Bouchez, Laure; Markovi?, Dean; Varela-Alvarez, Adrián; Sordo, José Angel

2007-10-01

141

Infusing the Chemistry Curriculum with Green Chemistry Using Real-World Examples, Web Modules, and Atom Economy in Organic Chemistry Courses  

ERIC Educational Resources Information Center

Green chemistry is the awareness of the damaging environmental effects due to chemical research and inventions. There is emphasis on a need to include green chemistry in synthesis with atom economy in organic chemistry curriculum to ensure an environmentally conscious future generation of chemists, policy makers, health professionals and business…

Cann, Michael C.; Dickneider, Trudy A.

2004-01-01

142

Aging of organic aerosol components via condensed-phase radical chemistry (Invited)  

NASA Astrophysics Data System (ADS)

The chemical evolution (aging) of organic aerosol, in which condensed-phase species undergo further reactions to form lower-volatility oxidized products, may be an important process in the lifecycle of atmospheric organic aerosol. However the chemistry and significance of various aging processes are not well-constrained at present, in part because of the number of different phases in which they can occur. In addition to oxidation chemistry in the gas phase and at the air-particle interface, oxidative aging may occur within different condensed phases, including liquid water and the condensed organic phase. Here we describe laboratory experiments aimed at probing reactivity within such condensed phases, via the direct generation of radicals within model aerosol particles. Studies are carried out using submicron particles (rather than bulk solutions) in order to simulate the partitioning conditions of the atmosphere, and reaction kinetics and products are monitored using aerosol mass spectrometry. For reactions within the condensed organic phase, alkyl and alkoxy radicals are formed from the direct UV photolysis of large alkyl iodides and alkyl nitrites, respectively. The changing chemical composition of the irradiated particles points to an important role of reactions between organic radicals and other organic aerosol components, leading to a combination of functionalization, oligomerization, and fragmentation/volatilization reactions. However, rapid oxidation of the organic species is not observed, presumably due to the relatively low concentration of dissolved molecular oxygen within the condensed organic phase. For experiments involving chemistry within liquid water droplets, significantly stronger oxidative conditions are accessed, leading to substantial oxidation and fragmentation of the dissolved organic compounds. These experiments provide insight into the roles of chemical structure and phase (liquid-water vs. condensed-organic) on the reactivity and aging products of organic aerosol components.

Kroll, J. H.; Carrasquillo, A. J.; Daumit, K. E.; Kessler, S. H.; Nah, T.; Wilson, K. R.

2013-12-01

143

Solution Calorimetry Experiments for Physical Chemistry.  

ERIC Educational Resources Information Center

Presents two experiments: the first one measures the heat of an exothermic reaction by the reduction of permanganate by the ferris ion; the second one measures the heat of an endothermic process, the mixing of ethanol and cyclohexane. Lists tables to aid in the use of the solution calorimeter. (MVL)

Raizen, Deborah A.; And Others

1988-01-01

144

A Novel W-Tube for Microscale Experiments in Chemistry  

Microsoft Academic Search

There are some experiments in chemistry where there is a need to test for the presence or absence of a certain gas. The experimental setup for these tests requires appreciable quantities of chemicals, time, and specialized apparatus. A simple W-tube is described to perform these tests quickly and economically at the microscale level.

H. O. Gupta

2007-01-01

145

Organic Chemistry Self Instructional Package 3: Alkanes-Homologous Series and Isomerism.  

ERIC Educational Resources Information Center

This booklet, one of a series of 17 developed at Prince George's Community College, Largo, Maryland, provides an individualized, self-paced undergraduate organic chemistry instruction module designed to augment any course in organic chemistry but particularly those taught using the text "Organic Chemistry" by Morrison and Boyd. The entire series…

Zdravkovich, V.

146

Organic Chemistry Self Instructional Package 7: Alkenes-Nomenclature and Isomerism.  

ERIC Educational Resources Information Center

This booklet, one of a series of 17 developed at Prince George's Community College, Largo, Maryland, provides an individualized, self-paced undergraduate organic chemistry instruction module designed to augment any course in organic chemistry but particularly those taught using the text "Organic Chemistry" by Morrison and Boyd. The entire series…

Zdravkovich, V.

147

The THS experiment: probing Titan's atmospheric chemistry at low temperature  

NASA Astrophysics Data System (ADS)

In Titan’s atmosphere, a complex chemistry between N2 and CH4 occurs at temperatures lower than 200K and leads to the production of heavy molecules and subsequently solid aerosols that form the haze surrounding Titan. The Titan Haze Simulation (THS) experiment has been developed at the NASA Ames COSmIC facility to study Titan’s atmospheric chemistry at low temperature in order to help interpret Cassini’s observational data. In the THS, the chemistry is simulated by plasma in the stream of a supersonic expansion. With this unique design, the gas is jet-cooled to Titan-like temperature 150K) before inducing the chemistry by plasma, and remains at low temperature in the plasma discharge 200K). Different N2-CH4-based gas mixtures can be injected in the plasma, with or without the addition of heavier precursors present as trace elements on Titan. Both the gas phase and solid phase products resulting from the plasma-induced chemistry can be monitored and analyzed using a combination of complementary in situ and ex situ diagnostics.Here we present the complementary results of two studies of the gas and solid phase. A Mass spectrometry analysis of the gas phase has demonstrated that the THS experiment is a unique tool to probe the first and intermediate steps as well as specific chemical pathways of Titan’s atmospheric chemistry at Titan-like temperature. The more complex chemistry, observed in the gas phase when adding trace elements to the initial N2-CH4 mixture, has also been confirmed by an extensive study of the solid phase products: Scanning Electron Microscopy images have shown that aggregates produced in N2-CH4-C2H2-C6H6 mixtures (up to 5 ?m in diameter) are much larger than those produced in N2-CH4 mixtures (0.1-0.5 ?m), and Nuclear Magnetic Resonance results support a growth evolution of the chemistry when adding acetylene to the N2-CH4 mixture, resulting in the production of more complex hydrogen bonds than with a simple N2-CH4 mixture.These complementary studies show the high potential of THS to better understand Titan’s chemistry and the origin of aerosol formation.AcknowledgmentsThis research is supported by NASA SMD PATM.

Sciamma-O'Brien, Ella; Upton, Kathleen; Beauchamp, Jack L; Salama, Farid

2014-06-01

148

Integration of Computational and Preparative Techniques to Demonstrate Physical Organic Concepts in Synthetic Organic Chemistry: An Example Using Diels-Alder Reaction  

ERIC Educational Resources Information Center

The Diels-Alder reaction is used as an example for showing the integration of computational and preparative techniques, which help in demonstrating the physical organic concepts in synthetic organic chemistry. These experiments show that the students should not accept the computational results without questioning them and in many Diels-Alder…

Palmer, David R. J.

2004-01-01

149

Synthetic organic chemistry based on small ring compounds.  

PubMed

Small ring systems are important topics in both organic and inorganic chemistry, and draw considerable attention from both theoretical and preparative perspectives. This review intends to summarize the studies, focusing on the preparative aspects, that have been carried out in our laboratory. Namely, synthesis of (+)- and (-)-alpha-cuparenone, (+)-ipomeamarone, (+)-epiipomeamarone, (-)-ngaione, (-)-alpha-bisabolol, (-)-aplysin, (-)-debromoaplysin, (-)-mesembrine, (-)-filiformin, (-)-debromofiliformin, and (-)-4-deoxyverrucarol via successive asymmetric epoxidation and enantiospecific ring expansion of cyclopropylidenes, (+)-equilenin via successive ring expansion-insertion reaction, estrone, estradiol, chenodeoxycholic acid, 19-norspironolactone, 19-nordeoxycorticosterone, cortisone, adrenosterone, 11-oxoprogesterone, and 1alpha,25-dihydroxyvitamin D3 via intramolecular cycloaddition reaction of o-quinodimethanes. Medicinal chemistry aiming at developing a new type of anti-influenza agent, novel reaction mode of electrocyclic reaction, and substituent effect on that reaction are also discussed. PMID:17603183

Nemoto, Hideo

2007-07-01

150

Gender Differences in Cognitive and Noncognitive Factors Related to Achievement in Organic Chemistry.  

ERIC Educational Resources Information Center

Examines the relationships between organic chemistry achievement and a number of cognitive and noncognitive variables, and explores whether gender differences existed for any of these relationships. Concludes that general chemistry grade, ACT-math score, and motivation are significant predictors of organic chemistry achievement. Indicates gender…

Turner, Ronna C.; Lindsay, Harriet A.

2003-01-01

151

The chemistry of cyborgs--interfacing technical devices with organisms.  

PubMed

The term "cyborg" refers to a cybernetic organism, which characterizes the chimera of a living organism and a machine. Owing to the widespread application of intracorporeal medical devices, cyborgs are no longer exclusively a subject of science fiction novels, but technically they already exist in our society. In this review, we briefly summarize the development of modern prosthetics and the evolution of brain-machine interfaces, and discuss the latest technical developments of implantable devices, in particular, biocompatible integrated electronics and microfluidics used for communication and control of living organisms. Recent examples of animal cyborgs and their relevance to fundamental and applied biomedical research and bioethics in this novel and exciting field at the crossroads of chemistry, biomedicine, and the engineering sciences are presented. PMID:24288270

Giselbrecht, Stefan; Rapp, Bastian E; Niemeyer, Christof M

2013-12-23

152

Aqueous-Phase Palladium-Catalyzed Coupling. A Green Chemistry Laboratory Experiment  

NASA Astrophysics Data System (ADS)

An upper-level inorganic/organic experiment presents important concepts in modern green chemistry. A water-soluble modified triphenylphosphine ligand is prepared and used to prepare a water-soluble palladium catalyst. The palladium catalyst is formed in situ and used for the aqueous, homogenous, palladium-catalyzed cross-coupling reaction of iodobenzene and diethyl phosphite. The product is diethyl phenylphosphonate.

Featured on the Cover

Harper, Brandy A.; Chance Rainwater, J.; Birdwhistell, Kurt; Knight, D. Andrew

2002-06-01

153

PAPER www.rsc.org/obc | Organic & Biomolecular Chemistry Cyclooctyne-based reagents for uncatalyzed click chemistry  

E-print Network

PAPER www.rsc.org/obc | Organic & Biomolecular Chemistry Cyclooctyne-based reagents for uncatalyzed click chemistry: A computational survey Kimberly Chenoweth, David Chenoweth§ and William A. Goddard III* Received 12th June 2009, Accepted 16th September 2009 First published as an Advance Article on the web 9th

Goddard III, William A.

154

Analysis of the Effect of Sequencing Lecture and Laboratory Instruction on Student Learning and Motivation Towards Learning Chemistry in an Organic Chemistry Lecture Course  

ERIC Educational Resources Information Center

Exposure to organic chemistry concepts in the laboratory can positively affect student performance, learning new chemistry concepts and building motivation towards learning chemistry in the lecture. In this study, quantitative methods were employed to assess differences in student performance, learning, and motivation in an organic chemistry

Pakhira, Deblina

2012-01-01

155

Argumentation in the Chemistry Laboratory: Inquiry and Confirmatory Experiments  

NASA Astrophysics Data System (ADS)

One of the goals of science education is to provide students with the ability to construct arguments—reasoning and thinking critically in a scientific context. Over the years, many studies have been conducted on constructing arguments in science teaching, but only few of them have dealt with studying argumentation in the laboratory. Our research focuses on the process in which students construct arguments in the chemistry laboratory while conducting various types of experiments. It was found that inquiry experiments have the potential to serve as an effective platform for formulating arguments, owing to the features of this learning environment. The discourse during inquiry-type experiments was found to be rich in arguments, whereas that during confirmatory-type experiments was found to be sparse in arguments. The arguments, which were developed during the discourse of an open inquiry experiment, focus on the hypothesis-building stage, analysis of the results, and drawing appropriate conclusions.

Katchevich, Dvora; Hofstein, Avi; Mamlok-Naaman, Rachel

2013-02-01

156

Gender Differences in Cognitive and Noncognitive Factors Related to Achievement in Organic Chemistry  

NASA Astrophysics Data System (ADS)

For many college students in the sciences, organic chemistry poses a difficult challenge. Indeed, success in organic chemistry has proven pivotal in the careers of a vast number of students in a variety of science disciplines. A better understanding of the factors that contribute to achievement in this course should contribute to efforts to increase the number of students in the science disciplines. Further, an awareness of gender differences in factors associated with achievement should aid efforts to bolster the participation of women in chemistry and related disciplines. Using a correlation research design, the individual relationships between organic chemistry achievement and each of several cognitive variables and noncognitive variables were assessed. In addition, the relationships between organic chemistry achievement and combinations of these independent variables were explored. Finally, gender- and instructor-related differences in the relationships between organic chemistry achievement and the independent variables were investigated. Cognitive variables included the second-semester general chemistry grade, the ACT English, math, reading, and science-reasoning scores, and scores from a spatial visualization test. Noncognitive variables included anxiety, confidence, effectance motivation, and usefulness. The second-semester general chemistry grade was found to be the best indicator of performance in organic chemistry, while the effectiveness of other predictors varied between instructors. In addition, gender differences were found in the explanations of organic chemistry achievement variance provided by this study. In general, males exhibited stronger correlations between predictor variables and organic chemistry achievement than females.

Turner, Ronna C.; Lindsay, Harriet A.

2003-05-01

157

Quantum chemistry simulation on quantum computers: theories and experiments.  

PubMed

It has been claimed that quantum computers can mimic quantum systems efficiently in the polynomial scale. Traditionally, those simulations are carried out numerically on classical computers, which are inevitably confronted with the exponential growth of required resources, with the increasing size of quantum systems. Quantum computers avoid this problem, and thus provide a possible solution for large quantum systems. In this paper, we first discuss the ideas of quantum simulation, the background of quantum simulators, their categories, and the development in both theories and experiments. We then present a brief introduction to quantum chemistry evaluated via classical computers followed by typical procedures of quantum simulation towards quantum chemistry. Reviewed are not only theoretical proposals but also proof-of-principle experimental implementations, via a small quantum computer, which include the evaluation of the static molecular eigenenergy and the simulation of chemical reaction dynamics. Although the experimental development is still behind the theory, we give prospects and suggestions for future experiments. We anticipate that in the near future quantum simulation will become a powerful tool for quantum chemistry over classical computations. PMID:22652702

Lu, Dawei; Xu, Boruo; Xu, Nanyang; Li, Zhaokai; Chen, Hongwei; Peng, Xinhua; Xu, Ruixue; Du, Jiangfeng

2012-07-14

158

Advanced Experiments in Nuclear Science, Volume I: Advanced Nuclear Physics and Chemistry Experiments.  

ERIC Educational Resources Information Center

The experiments in this manual represent state-of-the-art techniques which should be within the budgetary constraints of a college physics or chemistry department. There are fourteen experiments divided into five modules. The modules are on X-ray fluorescence, charged particle detection, neutron activation analysis, X-ray attenuation, and…

Duggan, Jerome L.; And Others

159

COMMUNICATION www.rsc.org/obc | Organic & Biomolecular Chemistry Rigid-rod pushpull naphthalenediimide photosystems  

E-print Network

COMMUNICATION www.rsc.org/obc | Organic & Biomolecular Chemistry Rigid-rod push of push­pull rods on self-organization, pho- toinduced charge separation and photosynthetic activity of pyrene 12, reaction of the resulting dichlorodianhydride first a Department of Organic Chemistry

Candea, George

160

Wet Chemistry experiments on the 2007 Phoenix Mars Scout Lander mission: Data analysis and results  

E-print Network

Wet Chemistry experiments on the 2007 Phoenix Mars Scout Lander mission: Data analysis and results performed using the Wet Chemistry Laboratories on the 2007 Phoenix Mars Scout Lander. One soil sample: Kounaves, S. P., et al. (2010), Wet Chemistry experiments on the 2007 Phoenix Mars Scout Lander mission

Kounaves, Samuel P.

161

Analytical and separation chemistry by taking advantage of organic photochromism combined with macrocyclic chemistry.  

PubMed

Photochromic crown compounds, such as monomeric and polymeric crown compounds incorporating spirobenzopyran, spironaphthooxazine, spirobenzothiapyran, Malachite Green, and Crystal Violet moieties, were synthesized for applications in the fields of analytical and separation chemistry. The photochromic crown compounds, especially crowned spirobenzopyran derivatives, were applied to metal ion extraction, extraction spectrophotometry, membrane transport, and ion chromatography, the sensitivity and selectivity of which were controlled and enhanced photochemically. Also, micelles and vesicles containing lipophilic crowned spirobenzopyrans and Malachite Greens were tested for their usefulness in spectrophotometric and fluorometric metal-ion determination and photocontrol of organic substance in aqueous systems. The polymeric crowned spirobenzopyrans were tried to use as a photochemical valve based on photochemical rheology changes. Moreover, attempts were made to directly observe photoinduced aggregation of the spirobenzopyran moiety and photoresponsive rheology changes of the polymeric crowned spirobenzopyran, by using chemical force microscopy. PMID:19139568

Kimura, Keiichi; Nakahara, Yoshio

2009-01-01

162

Lesson Planner for Demonstrations in Organic Chemistry Videodisc  

NASA Astrophysics Data System (ADS)

Lesson Planner is a Microsoft Excel (1) macro that generates barcodes for video included on the Demonstrations in Organic Chemistry videodisc (2). It allows instructors who do not have computer control capability for their videodisc player, but do have a barcode reader, to prepare customized lessons for use in the classroom or laboratory. There is no need to flip through pages in the documentation manual or photocopy pages of barcodes and physically cut and paste them to follow your lecture notes. Lesson Planner includes a complete list of the demonstrations and all sections and subsections included on the videodisc. You simply select the entire demos, sections, or subsections of demos you want to include in your presentation and add them to a lesson list with a mouse click. Lesson Planner generates a list of your selections with barcodes to access the correct video frames. Simply print a copy of the lesson on a laser printer and you are ready to go.

Surovell, Todd A.

1995-09-01

163

Electrochemical injection of organic corrosion inhibitors into carbonated cementitious materials: Part 1. Effects on pore solution chemistry  

Microsoft Academic Search

This series of investigations was intended to clarify phenomena associated with electrochemical injection of the organic base corrosion inhibitors, ethanolamine and guanidine, into carbonated concrete. In Part 1, experiments were conducted with laminated specimens of carbonated cement paste, that were specially designed to facilitate analysis with adequate spatial resolution to assess changes in their pore solution phase chemistry after they

S. Sawada; J. Kubo; C. L. Page; M. M. Page

2007-01-01

164

Irradiated Benzene Ice Provides Clues to Meteoritic Organic Chemistry  

NASA Technical Reports Server (NTRS)

Aromatic hydrocarbons account for a significant portion of the organic matter in carbonaceous chondrite meteorites, as a component of both the low molecular weight, solvent-extractable compounds and the insoluble organic macromolecular material. Previous work has suggested that the aromatic compounds in carbonaceous chondrites may have originated in the radiation-processed icy mantles of interstellar dust grains. Here we report new studies of the organic residue made from benzene irradiated at 19 K by 0.8 MeV protons. Polyphenyls with up to four rings were unambiguously identified in the residue by gas chromatography-mass spectrometry. Atmospheric pressure photoionization Fourier transform mass spectrometry was used to determine molecular composition, and accurate mass measurements suggested the presence of polyphenyls, partially hydrogenated polyphenyls, and other complex aromatic compounds. The profile of low molecular weight compounds in the residue compared well with extracts from the Murchison and Orgueil meteorites. These results are consistent with the possibility that solid phase radiation chemistry of benzene produced some of the complex aromatics found in meteorites.

Callahan, Michael Patrick; Gerakines, Perry Alexander; Martin, Mildred G.; Hudson, Reggie L.; Peeters, Zan

2013-01-01

165

Preparation of a D-Glucose-Derived Alkene. An E2 Reaction for the Undergraduate Organic Chemistry Laboratory  

NASA Astrophysics Data System (ADS)

As the carbohydrates continue to gain attention for their central role in numerous areas of chemistry and biology, there is a growing need for experiments at the undergraduate level that highlight these fascinating compounds. In this article we describe a simple two-step laboratory experiment that may be used to highlight several important concepts introduced in sophomore organic chemistry, as applied to compounds of potential biological interest. The sequence begins with commercially available "diacetone glucose," which is converted to the highly crystalline tosylate derivative. Upon treatment of compound 2 with potassium tert-butoxide in THF solution, the alkene (3-deoxy-1,2:5,6-di-O-isopropylidene- a- l">D -erythro-hex-3-enofuranose) is formed via an E2 reaction. The synthetic sequence allows for discussion of various concepts within organic chemistry, as well as for the application of analytical techniques such as polarimetry and one- and two-dimensional NMR.

Norris, Peter; Fluxe, Andrew

2001-12-01

166

Comparing Recent Organizing Templates for Test Content between ACS Exams in General Chemistry and AP Chemistry  

ERIC Educational Resources Information Center

Two different versions of "big ideas" rooted content maps have recently been published for general chemistry. As embodied in the content outline from the College Board, one of these maps is designed to guide curriculum development and testing for advanced placement (AP) chemistry. The Anchoring Concepts Content Map for general chemistry

Holme, Thomas

2014-01-01

167

Effects of additional nonmethane volatile organic compounds, organic nitrates, and direct emissions of oxygenated organic species on global tropospheric chemistry  

Microsoft Academic Search

This work evaluates the sensitivity of tropospheric ozone and its precursors to the representation of nonmethane volatile organic compounds (NMVOCs) and organic nitrates. A global 3-D tropospheric chemistry\\/transport model (IMPACT) has been exercised initially using the GEOS-Chem chemical reaction mechanism. The model was then extended by adding emissions and photochemical reactions for aromatic and terpenoid hydrocarbons, and by adding explicit

Akinori Ito; Sanford Sillman; Joyce E. Penner

2007-01-01

168

Challenges in the directed evolution of stereoselective enzymes for use in organic chemistry  

Microsoft Academic Search

Directed evolution constitutes an ideal method for engineering essentially any catalytic parameter of enzymes for application in synthetic organic chemistry and biotechnology, including thermostability, substrate scope and enantioselectivity. Stereoselectivity is especially important when applying biocatalysts to synthetic organic chemistry. This article focuses on recent methodology developments in laboratory evolution of stereoselective enzymes, hydrolases and monooxygenases serving as the enzymes. Iterative

M. T. Reetz; G. P. L. Krebs

2011-01-01

169

The Use of Computer-Based Instruction in Undergraduate Organic Chemistry.  

ERIC Educational Resources Information Center

Thirty-two computer-based lesson modules in organic chemistry were developed at the University of Texas (Austin) over an 18-month period and evaluated in varying classroom situations for three semesters starting in the Fall of 1972. The modules were designed as supplements to the traditional organic chemistry course of the University. As such,…

Culp, George H.

170

FOUR DECADES OF ORGANIC CHEMISTRY OF closo-BORANES: A SYNTHETIC TOOLBOX FOR CONSTRUCTING LIQUID CRYSTAL  

E-print Network

-borane chemistry and applica- tions of inorganic-organic hybrid materials5 . High chemical, thermal CRYSTAL MATERIALS. A REVIEW Piotr KASZYNSKI Organic Materials Research Group, Chemistry Department, containing 198 references, is designed as a synthetic manual for materials chemists and focuses on methods

Kaszynski, Piotr

171

The Influence of First-Year Chemistry Students' Learning Experiences on Their Educational Choices  

ERIC Educational Resources Information Center

The research reported here examined factors that influence student tertiary level chemistry enrolment choices. Students enrolled in a first-year chemistry class were surveyed, using the Chemistry Attitudes and Experiences Questionnaire (CAEQ), three times throughout their academic year: at the start of the year (n=126), the end of the first…

Dalgety, Jacinta; Coll, Richard K.

2006-01-01

172

Factors related to achievement in sophomore organic chemistry at the University of Arkansas  

NASA Astrophysics Data System (ADS)

The purpose of this study was to identify the significant cognitive and non-cognitive variables that related to achievement in the first semester of organic chemistry at the University of Arkansas. Cognitive variables included second semester general chemistry grade, ACT composite score, ACT English, mathematics, reading, and science reasoning subscores, and spatial ability. Non-cognitive variables included anxiety, confidence, effectance motivation, and usefulness. Using a correlation research design, the individual relationships between organic chemistry achievement and each of the cognitive variables and non-cognitive variables were assessed. In addition, the relationships between organic chemistry achievement and combinations of these independent variables were explored. Finally, gender- and instructor-related differences in the relationships between organic chemistry achievement and the independent variables were investigated. The samples consisted of volunteers from the Fall 1999 and Fall 2000 sections of Organic Chemistry I at the University of Arkansas. All students in each section were asked to participate. Data for spatial ability and non-cognitive independent variables were collected using the Purdue Visualization of Rotations test and the modified Fennema-Sherman Attitude Scales. Data for other independent variables, including ACT scores and second semester general chemistry grades, were obtained from the Office of Institutional Research. The dependent variable, organic chemistry achievement, was measured by each student's accumulated points in the course and consisted of scores on quizzes and exams in the lecture section only. These totals were obtained from the lecture instructor at the end of each semester. Pearson correlation and stepwise multiple regression analyses were used to measure the relationships between organic chemistry achievement and the independent variables. Prior performance in chemistry as measured by second semester general chemistry grade was the best indicator of performance in organic chemistry. The importance of other independent variables in explaining organic chemistry achievement varied between instructors. In addition, gender differences were found in the explanations of organic chemistry achievement variance provided by this study. In general, males exhibited stronger correlations between independent variables and organic chemistry achievement than females. The report contains 19 tables detailing the statistical analyses. Suggestions for improved practice and further research are also included

Lindsay, Harriet Arlene

173

Organic Chemistry, 2nd Edition (by Paula Y. Bruice)  

NASA Astrophysics Data System (ADS)

Prentice Hall: Englewood Cliffs, NJ, 1998, xxx +1256 pp, 6 appendices. ISBN 0-13-841925-6. $99. The author has made some constructive changes to the second edition of this visually pleasing book. The chapter order has been rearranged so that all of spectroscopy is covered in two adjoining chapters (new problems combining NMR and IR have been added), all of the chapters on bioorganic chemistry are grouped together (information on reducing sugars has been added), and the last section now covers heterocycles, pericyclic reactions, polymer synthesis, multistep synthetic strategies, and drug design. The publisher offers additional material at its Web site and a paperback for students assisting them in using the Internet. The ChemCentral Organic Web site has problem sets to supplement each chapter (including hints for struggling students) and animations of molecules undergoing reactions. In addition the Web site provides syllabus construction software for instructors. The accompanying study guide/solutions manual, written by the textbook author, contains a glossary, answers to chapter problems, and a practice test (for the first twenty chapters). There are sections called "special topics" which offer in-depth treatment of pH, pKa, buffers, and the electron-pushing formalism.

Katz, Marlene G.

1998-11-01

174

General Chemistry and Cellular and Molecular Biology: An Experiment in Curricular Symbiosis  

NASA Astrophysics Data System (ADS)

During the 1998-99 academic year, with the support of the Howard Hughes Medical Institute, we co-taught integrated courses in general chemistry and cell biology to 23 first-year students. The double course was organized around six units: I. Energetics: Harvesting (Bio)Chemical Energy; II. The Regulation of Biological Processes: Chemical Kinetics and Equilibrium; III. Membranes and Electrochemical Gradients; IV. Acids and Bases and the Regulation of pH; V. Intracellular Compartments and Transport; and VI. Cellular Communication. The chemistry and biology were both taught in a manner meant to enhance understanding of these major themes and to emphasize the relationships between the two disciplines. Both of us were present for all class sessions and shared teaching responsibilities. The examinations, which corresponded to the units, also stressed the interdependence of biology and chemistry. The laboratory components were not integrated; rather the students were dispersed among laboratory sections shared with students from more traditional lecture sections. The paper reports on this experiment in curricular symbiosis, which proved to be a challenging and rewarding learning experience for both the students and us.

Truman Schwartz, A.; Serie, Jan

2001-11-01

175

Chemistry  

NSDL National Science Digital Library

Finds ChemEd DL resources related to the sections of the General Chemistry textbook, Chemistry, by Kenneth W. Whitten, Raymond E. Davis, M. Larry Peck, George G. Stanley published by Brooks/Cole, 2010.

176

Peer-reviewed manuscript of the article published in Organic & Biomolecular Chemistry, 2010, 8, 864-872  

E-print Network

Peer-reviewed manuscript of the article published in Organic & Biomolecular Chemistry, 2010, 8, 864-872 Reproduced by permission of The Royal Society of Chemistry http://www.rsc.org/publishing/journals/OB/article,version1-11Sep2010 Author manuscript, published in "Organic & Biomolecular Chemistry / Organic

Boyer, Edmond

177

Chemistry of secondary organic aerosol: Formation and evolution of low-volatility organics in the atmosphere  

NASA Astrophysics Data System (ADS)

Secondary organic aerosol (SOA), particulate matter composed of compounds formed from the atmospheric transformation of organic species, accounts for a substantial fraction of tropospheric aerosol. The formation of low-volatility (semivolatile and possibly nonvolatile) compounds that make up SOA is governed by a complex series of reactions of a large number of organic species, so the experimental characterization and theoretical description of SOA formation presents a substantial challenge. In this review we outline what is known about the chemistry of formation and continuing transformation of low-volatility species in the atmosphere. The primary focus is chemical processes that can change the volatility of organic compounds: (1) oxidation reactions in the gas phase, (2) reactions in the particle phase, and (3) continuing chemistry (in either phase) over several generations. Gas-phase oxidation reactions can reduce volatility by the addition of polar functional groups or increase it by the cleavage of carbon-carbon bonds; key branch points that control volatility are the initial attack of the oxidant, reactions of alkylperoxy (RO2) radicals, and reactions of alkoxy (RO) radicals. Reactions in the particle phase include oxidation reactions as well as accretion reactions, non-oxidative processes leading to the formation of high-molecular-weight species. Organic carbon in the atmosphere is continually subject to reactions in the gas and particle phases throughout its atmospheric lifetime (until lost by physical deposition or oxidized to CO or CO2), implying continual changes in volatility over the timescales of several days. The volatility changes arising from these chemical reactions must be parameterized and included in models in order to gain a quantitative and predictive understanding of SOA formation.

Kroll, Jesse H.; Seinfeld, John H.

2008-05-01

178

Making Sense of Olive Oil: Simple Experiments to Connect Sensory Observations with the Underlying Chemistry  

ERIC Educational Resources Information Center

In the last decade, our understanding of the chemistry of olive oil has dramatically improved. Here, the essential chemistry of olive oil and its important minor constituents is described and related to the typical sensory categories used to rate and experience oils: color, aroma, bitterness, and pungency. We also describe experiments to explore…

Blatchly, Richard A.; Delen, Zeynep; O'Hara, Patricia B.

2014-01-01

179

Thalidomide Makes a Comeback: A Case Discussion Exercise That Integrates Biochemistry and Organic Chemistry  

Microsoft Academic Search

The case discussion method, which involves teaching scientific theory in a framework that students can relate to their own world, is an interdisciplinary pedagogical tool. Therefore, case study exercises can be used to integrate biochemistry with other advanced chemistry courses. The case presented here can be used at the end of a second-semester organic chemistry course or in an introductory

Nicole Bennett; Kathleen Cornely

2001-01-01

180

ATR-FTIR Spectroscopy in the Undergraduate Chemistry Laboratory: Part II--A Physical Chemistry Laboratory Experiment on Surface Adsorption  

ERIC Educational Resources Information Center

Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy is a useful technique for measuring the infrared spectra of solids and liquids as well as probing adsorption on particle surfaces. The use of FTIR-ATR spectroscopy in organic and inorganic chemistry laboratory courses as well as in undergraduate research was presented…

Schuttlefield, Jennifer D.; Larsen, Sarah C.; Grassian, Vicki H.

2008-01-01

181

PERSPECTIVE: From computational quantum chemistry to computational biology: experiments and computations are (full) partners  

NASA Astrophysics Data System (ADS)

Computations are being integrated into biological research at an increasingly fast pace. This has not only changed the way in which biological information is managed; it has also changed the way in which experiments are planned in order to obtain information from nature. Can experiments and computations be full partners? Computational chemistry has expanded over the years, proceeding from computations of a hydrogen molecule toward the challenging goal of systems biology, which attempts to handle the entire living cell. Applying theories from ab initio quantum mechanics to simplified models, the virtual worlds explored by computations provide replicas of real-world phenomena. At the same time, the virtual worlds can affect our perception of the real world. Computational biology targets a world of complex organization, for which a unified theory is unlikely to exist. A computational biology model, even if it has a clear physical or chemical basis, may not reduce to physics and chemistry. At the molecular level, computational biology and experimental biology have already been partners, mutually benefiting from each other. For the perception to become reality, computation and experiment should be united as full partners in biological research.

Ma, Buyong; Nussinov, Ruth

2004-12-01

182

Microwave-Assisted Chemistry: A Rapid and Sustainable Route to Synthesis of Organics and Nanomaterials  

EPA Science Inventory

The use of emerging MW-assisted chemistry techniques in conjunction with benign reaction media is dramatically reducing chemical waste and reaction times in several organic syntheses and chemical transformations. This review summarizes recent developments in MW-assisted synthesis...

183

DIVISION S-2--SOIL CHEMISTRY Soil Organic Matter Composition in the Subhumid Ethiopian Highlands as Influenced  

E-print Network

DIVISION S-2--SOIL CHEMISTRY Soil Organic Matter Composition in the Subhumid Ethiopian Highlands organic matter (Zech structural composition of soil organic matter (SOM) in bulk soils and et al., 1997a and output of the soil because of mineral-uid-state 13 C nuclear magnetic resonance (NMR) spectroscopy were

Lehmann, Johannes

184

An expert performance approach to examining factors contributing to academic success in organic chemistry  

NASA Astrophysics Data System (ADS)

Successful completion of the introductory course in organic chemistry is a prerequisite for many graduate and professional science programs, yet the failure rate for this course is notoriously high. To date, there have been few studies examining factors contributing to academic success in organic chemistry. This study demonstrates that the online, longitudinal methods used by investigations of expert performance can examine and successfully identify factors contributing to academic success at the college level. Sixty-four students enrolled in introductory organic chemistry during the Fall 2007 and Spring 2008 semesters completed motivation questionnaires, interviews, diaries, and think-aloud reading and problem-solving tasks at three different points across a semester. Measures of spatial ability, general ability, and background preparation were also collected. Each measure was analyzed to determine significant differences between groups differing in grade-point average (GPA) prior to the start of the course and to identify predictors of organic chemistry grade. Variables measuring background preparation, problem-solving strategies and studying strategies were found to be the best predictors of academic success in organic chemistry. Implications for instruction in organic chemistry and effective studying behaviors are discussed.

Nandagopal, Kiruthiga

185

The Discovery-Oriented Approach to Organic Chemistry. 4. Epoxidation of p-Methoxy-trans-b-methylstyrene: An Exercise in NMR and IR Spectroscopy for Sophomore Organic Laboratories  

NASA Astrophysics Data System (ADS)

Epoxidation of alkenes using peroxyacids is one of the most fundamental reactions in organic chemistry, yet there are very few examples of laboratory experiments that illustrate this important reaction. We have developed a discovery-oriented lab experiment that illustrates epoxidation of alkenes as well as the reactivity of epoxides toward acids. The experiment involves reaction of p-methoxy-trans-b-methylstyrene (trans-anethole) with m-chloroperoxybenzoic acid (MCPBA), in both the absence and presence of a buffer, followed by product identification using 1H NMR, 13C NMR, and IR spectroscopy. The added element of discovery ensures that students' interest and enthusiasm are retained.

Centko, Rebecca S.; Mohan, Ram S.

2001-01-01

186

Size distribution dynamics reveal particle-phase chemistry in organic aerosol formation  

NASA Astrophysics Data System (ADS)

Organic aerosols are ubiquitous in the atmosphere and play a central role in climate, air quality and public health. The aerosol size distribution is key in determining its optical properties and cloud condensation nucleus activity. The dominant portion of organic aerosol is formed through gas-phase oxidation of volatile organic compounds, so-called secondary organic aerosol (SOA). Typical experimental measurements of SOA formation include total SOA mass and atomic oxygen-to-carbon ratio. These measurements, alone, are generally insufficient to reveal the extent to which condensed-phase reactions occur in conjunction with the multi-generation gas-phase photooxidation. Combining laboratory chamber experiments and kinetic gas-particle modeling for the dodecane SOA system, here we show that the presence of particle-phase chemistry is reflected in the evolution of the SOA size distribution as well as its mass concentration. Particle-phase reactions are predicted to occur mainly at the particle surface and the reaction products contribute more than half of the SOA mass. Chamber photooxidation with a mid-experiment aldehyde injection confirms that heterogeneous reaction of aldehydes with organic hydroperoxides forming peroxyhemiacetals can lead to a large increase in SOA mass. The results of the current work have a number of implications for SOA models. While the dynamics of an aerosol size distribution reflects the mechanism of growth, we demonstrate here that it provides a key constraint in interpreting laboratory and ambient SOA formation. This work, although carried out specifically for the long chain alkane, dodecane, is expected to be widely applicable to other major classes of SOA precursors. SOA consists of a myriad of organic compounds containing various functional groups, which can generally undergo heterogeneous/multiphase reactions forming low-volatility products such as oligomers and other high molecular mass compounds. If particle-phase chemistry is indeed central to SOA growth in general, the size-resolved SOA formation is better described in terms of kinetically limited condensational growth, rather than solely by thermodynamic equilibrium partitioning.

Shiraiwa, M.; Yee, L. D.; Schilling, K.; Loza, C. L.; Craven, J. S.; Zuend, A.; Ziemann, P. J.; Seinfeld, J.

2013-12-01

187

Motivational Beliefs and Learning Strategies in Organic Chemistry  

ERIC Educational Resources Information Center

Students enter college chemistry courses with different sources of motivation, appropriate or inappropriate assumptions about their probability of success and how to study. This study is theoretically aligned with self-regulated learning research. Clearly, academic performance is closely related to student motivational beliefs and learning…

Lynch, Douglas Jay; Trujillo, Hernando

2011-01-01

188

Filtrates & Residues: Hemoglobinometry--A Biochemistry Experiment that Utilizes the Principles of Transition Metal Chemistry.  

ERIC Educational Resources Information Center

Describes a chemistry experiment dealing with hemoglobinometry that can apply to transition metal chemistry, colorimetry, and biochemistry. Provides a detailed description of the experimental procedure, including discussions of the preparation of the cyanide reagent, colorimetric measurements, and waste disposal and treatment. (TW)

Giuliano, Vincenzo; Rieck, John Paul

1987-01-01

189

Incorporating Guided-Inquiry Learning into the Organic Chemistry Laboratory  

ERIC Educational Resources Information Center

Guided-inquiry experiments also known as discovery-based experiments, which combine the pedagogical advantages of open-inquiry methods with the practical advantages of expository experiments, are described. Unlike open-inquiry or problem-based experiments, guided-inquiry experiments could be readily adapted to large laboratory sections and induces…

Gaddis, Barbara A.; Schoffstall, Allen M.

2007-01-01

190

Modeling SOAaq Formation: Explicit Organic Chemistry in Cloud Droplets with CMAQ  

NASA Astrophysics Data System (ADS)

Aqueous multiphase chemistry in the atmosphere has a substantial impact on climate and can lead to air quality changes that adversely impact human health and the environment. The chemistry is complex because of the variety of compounds present in the atmosphere and the phase transitions associated with multiphase reactions. These reactions can lead to the formation of secondary organic aerosols (SOAAQ) in the atmosphere. When included, current photochemical models typically use a simple parameterization to describe SOAAQ formation. Here, we discuss the implementation of explicit aqueous SOA chemistry in a box model of the CMAQ 5.0.1 aqueous phase chemistry mechanism using the Kinetic PreProcessor (KPP). The expanded chemistry model includes reactions of glyoxal, methylglyoxal, and glycolaldehyde as precursors to form SOAAQ and is based on the mechanism from Lim et. al. 2010. The current aqueous phase chemistry module in CMAQ uses a forward Euler method to solve the system of oxidation equations, estimating the pH with a bisection method assuming electroneutrality, and multiphase processes are solved sequentially. This is not robust for systems with large dynamic range (e.g., multiphase systems), and inhibits expansion of the aqueous phase chemical mechanism to adequately incorporate the growing body of literature that describes multiphase organic chemistry. The KPP solver allows for all processes to be solved simultaneously and facilitates expansion of the current mechanism. Addition of explicit organic reactions and H2O2 photolysis in the KPP box model results in increased mass of organic aerosol and more realistic predictions. For particulate matter focused air quality management strategies to be effective, it is important that models move away from the yield-based approach currently used and expand to include more explicit organic chemistry.

Carlton, A. G.; Sareen, N.; Fahey, K.; Hutzell, W. T.

2013-12-01

191

Sterilization affects soil organic matter chemistry and bioaccumulation of spiked p,p'-DDE and anthracene by earthworms.  

PubMed

Laboratory experiments were conducted to assess the effects of soil sterilization on the bioavailability of spiked p,p'-DDE and anthracene to the earthworms Eisenia fetida and Lumbricus terrestris. Physical and chemical changes to soil organic matter (SOM) induced by sterilization were also studied. Uptake of both compounds added after soil was autoclaved or gamma irradiated increased for E. fetida. Sterilization had no effect on bioaccumulation of p,p'-DDE by L. terrestris, and anthracene uptake increased only in gamma-irradiated soils. Analyses by FT-IR and DSC indicate sterilization alters SOM chemistry and may reduce pollutant sorption. Chemical changes to SOM were tentatively linked to changes in bioaccumulation, although the effects were compound and species specific. Artifacts produced by sterilization could lead to inaccurate risk assessments of contaminated sites if assumptions derived from studies carried out in sterilized soil are used. Ultimately, knowledge of SOM chemistry could aid predictions of bioaccumulation of organic pollutants. PMID:20227150

Kelsey, Jason W; Slizovskiy, Ilya B; Peters, Richard D; Melnick, Adam M

2010-06-01

192

Structure & Reactivity in Organic, Biological and Inorganic Chemistry  

NSDL National Science Digital Library

This site is a collection of web-pages designed to support an integrated treatment of related topics from organic, inorganic and biochemistry. The topics are organized around common principles of structure or reactivity.

Schaller, Chris P.

193

Understanding the motivation and help-seeking experiences of adult, online chemistry students  

NASA Astrophysics Data System (ADS)

The purpose of this study was to identify and explain factors that motivate and assist adult, online chemistry students to both enroll and persist in successfully completing general chemistry. Secondarily, the study sought to identify aspects of the online education process that are most challenging for adult, online chemistry students. Using a three-step coding process, interview transcripts, photographs, and asynchronous discussion board postings completed by eleven study participants were analyzed. A grounded theory, the trellis theory of online learning, emerged from the data. This theory reveals how adult learners' motivation emerges from transformative realizations occurring within their lived experiences. Similarly, the trellis theory shows how adult learners' goals emerge from their situational standpoints, also rooted in lived experiences. Finally, the trellis theory depicts the five modes of learning that adult students tend to follow in the context of learning online chemistry. Implications for researchers, program administrators, and online chemistry educators are discussed.

Bannier, Betsy J.

194

A Mass Spectral Chlorine Rule for Use in Structure Determinations in Sophomore Organic Chemistry  

ERIC Educational Resources Information Center

The low-resolution mass spectrum of integral masses is used to determine the number of bromine and chlorine atoms in an organic compound. The chlorine rule is a tool suitable for use in structural determinations in first year organic chemistry and it is supported by the ability of sophomore-level students to successfully determine n and m from the…

Gross, Ray A., Jr.

2004-01-01

195

The influence of microbial communities, management, and soil texture on soil organic matter chemistry  

Microsoft Academic Search

Soil organic matter dynamics following land-use change remain difficult to predict because of the complex biological, physical, and chemical mechanisms that control C turnover. We examined twelve sites, representing four broad land-use types (cultivated agriculture, pine forest, hardwood forest, and pasture), in the South Carolina Piedmont to determine whether variation in organic matter chemistry was linked to management, soil edaphic

A. Stuart Grandy; Michael S. Strickland; Christian L. Lauber; Mark A. Bradford; Noah Fierer

2009-01-01

196

The effect of organic amendments on phosphorus chemistry in a potato cropping system  

Microsoft Academic Search

Understanding the role of organic matter in increasing phosphorus (P) bioavailability may lead to the development of cropping systems that can increase the efficiency of soil P use and allow growers to lessen inputs of P fertilizer to crops. This study examined the effects of organic matter additions on soil phosphorus (P) chemistry in a potato (Solanum tuberosum L.) cropping

M. S Erich; C. B Fitzgerald; G. A Porter

2002-01-01

197

The Fourier Transform in Chemistry-NMR, Part 3. Multiple-Pulse Experiments.  

ERIC Educational Resources Information Center

Described are six multipulse experiments with an emphasis on their application to common problems in chemistry. Exercises in relaxation time measurement, spin echoes, and polarization transfer are proposed. (CW)

Williams, Kathryn R.; King, Roy W.

1990-01-01

198

Cross-Disciplinary Thermoregulation and Sweat Analysis Laboratory Experiences for Undergraduate Chemistry and Exercise Science Students  

NSDL National Science Digital Library

This article describes a qualitative evaluation of Cross-Disciplinary health sciences undergraduate laboratory experiences in which concepts and students from two distinct disciplines (chemistry and exercise physiology) combined to study exercise thermoregulation and sweat analysis.

2011-06-01

199

Synthesis of Organic Matter of Prebiotic Chemistry at the Protoplanetary Disc  

NASA Astrophysics Data System (ADS)

We have carried out scanning electron microscopic examination of CM carbonaceous chondrites meteorites Migey, Murchison, Staroe Boriskino aged more than 4.56 billion years (about 50 million years from the beginning of the formation of the Solar system). Our study confirmed the conclusion of Rozanov, Hoover and other researchers about the presence of microfossils of bacterial origin in the matrix of all these meteorites. Since the time of the Solar system formation is 60 - 100 million years, the primary biocenosis emerged in the protoplanetary disc of the Solar system before meteorites or simultaneously with them. It means that prebiological processes and RNA world appeared even earlier in the circumsolar protoplanetary disc. Most likely, this appearance of prebiotic chemistry takes place nowday in massive and medium-massive discs of the observed young stellar objects (YSO) class 0 and I. The timescale of the transition from chemical to biological evolution took less than 50 million years for the Solar system. Further evolution of individual biocenosis in a protoplanetary disc associated with varying physico-chemical conditions during the formation of the Solar system bodies. Biocenosis on these bodies could remove or develop under the influence of many cosmic factors and geological processes in the case of Earth. To complete the primary biosphere formation in short evolution time - millions of years - requires highly efficient chemical syntheses. In industrial chemistry for the efficient synthesis of ammonia, hydrogen cyanide, methanol and other organic species, that are the precursors to obtain prebiotic compounds, catalytic reactors of high pressure are used. Thus (1) necessary amount of the proper catalyst in (2) high pressure areas of the disc can trigger these intense syntheses. The disc contains the solids with the size from nanoparticle to pebble. Iron and magnesium is catalytically active ingredient for such solids. The puzzle is a way to provide hydrogen pressure inside the disc from tens to hundred atmospheres. We simulated unsteady processes in massive circumstellar discs around YSO class O and I. In the computational experiments, we have shown that at a certain stage of its evolution the circumstellar discs of gas and solids produces local areas of high pressure. According to the classical heterogeneous catalysis, a wide range of organic and prebiotic compounds could have been synthesized in these areas. Can we capture these areas of high pressure synthesis in observation of circumstellar discs? Due to the small sizes of such areas they can be hardly ever resolved even with the modern telescopes such as ALMA. However, we can try to detect their signatures in the disc, since the gas of the disc keep the set of organic synthesis products. The idea is to define the signature of the process using laboratory experiments. Varying gas temperature and pressure in laboratory setup we can carry out the catalytic high pressure syntheses and specify the set of gaseous products. These sets of organic compounds observed in the discs may serve as indicators of the emergence of high-pressure areas of prebiotic chemistry. Thus, there is a special interest to the study of YSO class 0 and I by means of observational astronomy. For these objects, first data on the presence of individual organic compounds in massive hydrogen-helium component of the discs appear. The origin of the organic compounds that are associated with chemical reactions in the discs should be separated from the set of organic compounds of the initial molecular cloud.

Snytnikov, Valeriy; Stoynovskaya, Olga; Rudina, Nina

200

Usnic Acid and the Intramolecular Hydrogen Bond: A Computational Experiment for the Organic Laboratory  

ERIC Educational Resources Information Center

A computational experiment is described for the organic chemistry laboratory that allows students to estimate the relative strengths of the intramolecular hydrogen bonds of usnic and isousnic acids, two related lichen secondary metabolites. Students first extract and purify usnic acid from common lichens and obtain [superscript 1]H NMR and IR…

Green, Thomas K.; Lane, Charles A.

2006-01-01

201

Preparation of Gold Nanoparticles Using Tea: A Green Chemistry Experiment  

ERIC Educational Resources Information Center

Assimilating green chemistry principles in nanotechnology is a developing area of nanoscience research nowadays. Thus, there is a growing demand to develop environmentally friendly and sustainable methods for the synthesis of nanoparticles that utilize nontoxic chemicals, environmentally benign solvents, and renewable materials to avoid their…

Sharma, R. K.; Gulati, Shikha; Mehta, Shilpa

2012-01-01

202

Theoretical Chemistry Comes Alive: Full Partner with Experiment.  

ERIC Educational Resources Information Center

The expected thrust for theoretical chemistry in the next decade will be to combine knowledge of fundamental chemical steps/interactions with advances in chemical dynamics, irreversible statistical mechanics, and computer technology to produce simulations of chemical systems with reaction site competition. A sample simulation (using the enzyme…

Goddard, William A., III

1985-01-01

203

Education & Experience B.S. Chemistry, University of California  

E-print Network

) Henry Dreyfus Teacher-Scholar Award (2001) U.S. Presidential Early Career Award for Scientists Award (1993) David L. Patrick Professor of Chemistry Tel 360-650-3128 Western Washington University Fax 360-650-2826 516 High St., Bellingham, WA 98225 david.patrick@wwu.edu http://atom.chem.wwu.edu/dept/facstaff/dpatrick/patrick

Patrick, David L.

204

Climate, Litter Chemistry, and Nitrogen Controls on Litter Decomposition and Organic Matter Stabilization  

NASA Astrophysics Data System (ADS)

Climate interacts with N availability and other factors to control organic matter decomposition rates and carbon cycling. We analyzed data from the LIDET (Long-Term Inter-site Decomposition Experiment Team) experiment to investigate the controls on litter decomposition rates and organic matter stabilization. Bags containing vegetative litter from different woody and herbaceous species were placed in 28 sites representing a wide array of biomes. Samples were collected approximately ten times, once per year for all sites except tropical sites, which were sampled every 3-6 months. Each sample was analyzed for total N, ash, lignin, and cellulose using near infrared reflectance spectroscopy. To account for water and temperature impacts on decomposition, we calculated a Climate Decomposition Index (CDI) for each site based on long term weather data. We then performed step-wise regression analyses to test how well CDI and litter chemistry were correlated with the amount of biomass remaining in litter bags after 1, 5, and 10 years. CDI was the primary control, accounting for 74, 48, and 58% of variability in biomass remaining at 1, 5, and 10 years, respectively. In addition to CDI, The C/N ratio of labile organic matter and lignin content significantly impacted biomass remaining at 1 and 5 years, while lignin and cellulose content were significant for biomass remaining at 10 years. Increased C/N ratio was associated with slower initial decomposition rate. Lignin content was positively, and cellulose negatively, correlated with long term organic matter stabilization. If CDI and lignin content were similar, then C/N did not influence long term stabilization. If N was not limiting, cellulose decomposed quickly.

DelGrosso, S.; Parton, W. J.; Adair, C.

2012-12-01

205

[Iatrophics and iatrochemistry: physica, chemistry and models of living organization].  

PubMed

Medical secularization which develops in Europe since XVIth century allows the human body to be considered as an autonomous physical being. Consequently, medicine tries to explain illness and health through the general rules of mechanics and chemistry. The development of medical systems - seen in terms of the two leading theories of iatrochemistry and iatrophysics, was centered around the problem of control in living objects, whose analysis is still useful in the present debate. Past and present are linked by a common effort towards the explanation of life phenomena, health and illness - despite the obvious methodological gaps of the different cultural periods. PMID:11625403

Fantini, B

1997-01-01

206

Effects of additional nonmethane volatile organic compounds, organic nitrates, and direct emissions of oxygenated organic species on global tropospheric chemistry  

NASA Astrophysics Data System (ADS)

This work evaluates the sensitivity of tropospheric ozone and its precursors to the representation of nonmethane volatile organic compounds (NMVOCs) and organic nitrates. A global 3-D tropospheric chemistry/transport model (IMPACT) has been exercised initially using the GEOS-Chem chemical reaction mechanism. The model was then extended by adding emissions and photochemical reactions for aromatic and terpenoid hydrocarbons, and by adding explicit representation of hydroxy alkyl nitrates produced from isoprene. Emissions of methanol, phenol, acetic acid and formic acid associated with biomass burning were also added. Results show that O3 increases by 20% in most of the troposphere, peroxyacetyl nitrate (PAN) increases by 30% over much of the troposphere and OH increases by 10%. NOx (NO + NO2) decreases near source regions and increases in remote locations, reflecting increased transport of NOx away from source regions by organic nitrates. The increase in O3 was driven largely by the increased role of PAN as a transporter of NOx and by the rerelease of NOx from isoprene nitrates. The increased PAN production was associated with increases in methyl glyoxal and hydroxyacetone. Comparison with measured values show reasonable agreement for O3 and PAN, but model measurement agreement does not either improve or degrade in the extended model. The extended model shows improved agreement with measurements for methanol, acetic acid and peroxypropional nitrate (PPN). Results from the extended model were consistent with measured alkyl nitrates and glycolaldehyde, but hydroxyacetone and methyl glyoxal were overestimated. The latter suggests that the effect of the isoprene nitrates is somewhat smaller than estimated here. Although the model measurement comparison does not show specific improvements with the extended model, it provides a more complete description of tropospheric chemistry that we believe is important to include.

Ito, Akinori; Sillman, Sanford; Penner, Joyce E.

2007-03-01

207

Art, Meet Chemistry; Chemistry, Meet Art: Case Studies, Current Literature, and Instrumental Methods Combined to Create a Hands-On Experience for Nonmajors and Instrumental Analysis Students  

ERIC Educational Resources Information Center

Case studies and current literature are combined with spectroscopic analysis to provide a unique chemistry experience for art history students and to provide a unique inquiry-based laboratory experiment for analytical chemistry students. The XRF analysis method was used to demonstrate to nonscience majors (art history students) a powerful…

Nivens, Delana A.; Padgett, Clifford W.; Chase, Jeffery M.; Verges, Katie J.; Jamieson, Deborah S.

2010-01-01

208

Spatial organization of stream water discharge and chemistry in forested headwaters  

NASA Astrophysics Data System (ADS)

It has long been known that, in small catchments, stream water discharge and chemistry are highly variable but the variability decreases gradually with an increase in the catchment area. Wood et al. (1988) showed that model calculations of infiltration and the runoff rate became constant above a certain threshold area. They defined the threshold area as the representative elementary area (REA) and stated that above the REA only minimum knowledge of the underlying parameters is needed to explain the stream water discharge and chemistry. Subsequently, empirical studies were conducted in several catchments. These studies all verified the existence of an REA in real catchments and indicated that the REA values differed among catchments. The results also suggested that the confluence processes of stream water discharge and chemistry differed among catchments. However, it has not been clarified how the confluence processes behave and why processes differ among catchments. One of the unclear things to resolve is whether the variability of discharge and chemistry among small catchments can be regarded as randomness or if it is organized. Two previous studies examined it and reported the opposite results. Woods et al. (1995) reported that organization was apparent from their observations of specific discharge. However, Asano and Uchida (2010) stated that their results for SiO2 could be regarded as randomness. These studies targeted different observed items and different catchments. Therefore, general knowledge about organization of stream water discharge and chemistry has not been obtained. We observed spatial variability of stream water discharge and chemistry and examined the existence of spatial organization by using the statistical method. Our objective was to elucidate whether the spatial organization exists about stream water discharge and chemistry. Observations were conducted in three forested catchments in Japan. Snapshot samplings of stream water discharge and chemistry were conducted at low flow conditions. We compared observed data with the theoretical line suggested by Woods et al. (1995). Our results showed that the spatial variability in observed items did not completely decrease along the theoretical line in any catchment. Furthermore, the results for dissolved matter were different from the results for specific discharge. Specific discharge showed higher average values in small catchments than in the entire catchment, and convergence of specific discharge occurred more quickly than did convergence of dissolved components. These results meant that the variability and convergence of stream water discharge and chemistry couldn't be regarded as simple mixing of randomly distributed variability and verified the existence of organization. We discussed the factor of forming the spatial organization by using conceptual model considering micro topography.

Egusa, T.; Ohte, N.; Oda, T.; Suzuki, M.

2013-12-01

209

Asymmetric aminocatalysis--gold rush in organic chemistry.  

PubMed

Catalysis with chiral secondary amines (asymmetric aminocatalysis) has become a well-established and powerful synthetic tool for the chemo- and enantioselective functionalization of carbonyl compounds. In the last eight years alone, this field has grown at such an extraordinary pace that it is now recognized as an independent area of synthetic chemistry, where the goal is the preparation of any chiral molecule in an efficient, rapid, and stereoselective manner. This has been made possible by the impressive level of scientific competition and high quality research generated in this area. This Review describes this "Asymmetric Aminocatalysis Gold Rush" and charts the milestones in its development. As in all areas of science, progress depends on human effort. PMID:18666089

Melchiorre, Paolo; Marigo, Mauro; Carlone, Armando; Bartoli, Giuseppe

2008-01-01

210

Filtrates and Residues: Saturated and Unsaturated Fats: An Organic Chemistry Demonstration.  

ERIC Educational Resources Information Center

Background information and procedures are provided for an experiment in which an oxidation reaction is used to distinguish saturated from unsaturated fats. Results of the experiment lead to discussions and investigations of such areas as digestion chemistry, enzymes, hydrogenation, and the relationship between heart disease and fat consumption.…

Broniec, Rick

1985-01-01

211

Interstellar chemistry recorded in organic matter from primitive meteorites.  

PubMed

Organic matter in extraterrestrial materials has isotopic anomalies in hydrogen and nitrogen that suggest an origin in the presolar molecular cloud or perhaps in the protoplanetary disk. Interplanetary dust particles are generally regarded as the most primitive solar system matter available, in part because until recently they exhibited the most extreme isotope anomalies. However, we show that hydrogen and nitrogen isotopic compositions in carbonaceous chondrite organic matter reach and even exceed those found in interplanetary dust particles. Hence, both meteorites (originating from the asteroid belt) and interplanetary dust particles (possibly from comets) preserve primitive organics that were a component of the original building blocks of the solar system. PMID:16675696

Busemann, Henner; Young, Andrea F; Alexander, Conel M O'd; Hoppe, Peter; Mukhopadhyay, Sujoy; Nittler, Larry R

2006-05-01

212

CHEMISTRY 322 ORGANIC CHEMISTRY Spring 2010 MWF 11:45-12:45 201A Reichardt Building  

E-print Network

/aromaticity Hybridization Stereochemistry Spectroscopy Nomenclature Mechanisms (including SN1, SN2, E1, E2, & electrophillic. Approximately 90 new organic reactions will be introduced with these functional groups. Many of the concepts

Wagner, Diane

213

Syllabus Organic Chemistry Laboratory CHEM 222, Session A, summer 2013  

E-print Network

.vitale@yale.edu), 145 SCL, 432-3964. Teaching assistants: TBA Required materials: Lab textbook: Techniques in Organic (no sandals, flip flops or ballet type), no earbuds or head phones. Thick sharpie markers® for writing

214

An Experimental Introduction to Organic Chemistry by Way of Ethene  

ERIC Educational Resources Information Center

Discusses the importance of ethene (ethylene) in industry and the pipeline grid in western Europe for transporting ethene. Describes methods for investigating organic compounds in school laboratories using ethene as the key compound. (JR)

Schmidt, Hans-Jurgen

1973-01-01

215

Developments in Analytical Chemistry: Acoustically Levitated Drop Reactors for Enzyme Reaction Kinetics and Single-Walled Carbon Nanotube-Based Sensors for Detection of Toxic Organic Phosphonates  

ERIC Educational Resources Information Center

Developments in analytical chemistry were made using acoustically levitated small volumes of liquid to study enzyme reaction kinetics and by detecting volatile organic compounds in the gas phase using single-walled carbon nanotubes. Experience gained in engineering, electronics, automation, and software development from the design and…

Field, Christopher Ryan

2009-01-01

216

A Research-Based Laboratory Course in Organic Chemistry  

ERIC Educational Resources Information Center

The development, implementation, evolution, and evaluation of a research-based laboratory course which was created as an alternative to more traditional laboratory instruction is described. The course was able to engage the students in devising and executing their own experiments, the satisfaction of determining the outcomes of those experiments,…

Newton, Thomas A.; Tracy, Henry J.; Prudente, Caryn

2006-01-01

217

Application of the organic on water reactions to prebiotic chemistry  

NASA Astrophysics Data System (ADS)

The old view that prebiotic reactions in water are hampered by the low solubility of the organic compounds in water is now being revised due to the discoveries of the reactions "on water". These reactions occur in the heterogeneous system comprising of the organic compounds and water. Unexpectedly, such reactions are extremely efficient; they often give quantitative yields, and are accelerated in the presence of water as compared to the organic solvents. These "on water" reactions are not the same as the "in water" reactions, which occur in solution, and are thus homogenous. Examples of the "on water" reactions include Diels-Alder, Claisen, Passerini and Ugi reactions, among many others. Some of these reactions are multicomponent, but give a single product. We survey a selected number of the "on water" reactions, which have a potential prebiotic applications.

Kolb, Vera M.

2012-10-01

218

Organic nitrogen chemistry during low-grade metamorphism  

NASA Astrophysics Data System (ADS)

Most of the organic nitrogen (N org) on Earth is disseminated in crustal sediments and rocks in the form of fossil nitrogen-containing organic matter. The chemical speciation of fossil N org within the overall molecular structure of organic matter changes with time and heating during burial. Progressive thermal evolution of organic matter involves phases of enhanced elimination of N org and ultimately produces graphite containing only traces of nitrogen. Long-term chemical and thermal instability makes the chemical speciation of N org a valuable tracer to constrain the history of sub-surface metamorphism and to shed light on the subsurface biogeochemical nitrogen cycle and its participating organic and inorganic nitrogen pools. This study documents the evolutionary path of N org speciation, transformation and elimination before and during metamorphism and advocates the use of X-ray photoelectron spectroscopy (XPS) to monitor changes in N org speciation as a diagnostic tool for organic metamorphism. Our multidisciplinary evidence from XPS, stable isotopes, traditional quantitative coal analyses, and other analytical approaches shows that at the metamorphic onset N org is dominantly present as pyrrolic and pyridinic nitrogen. The relative abundance of nitrogen substituting for carbon in condensed, partially aromatic systems (where N is covalently bonded to three C atoms) increases exponentially with increasing metamorphic grade, at the expense of pyridinic and pyrrolic nitrogen. At the same time, much N org is eliminated without significant nitrogen isotope fractionation. The apparent absence of Rayleigh-type nitrogen isotopic fractionation suggests that direct thermal loss of nitrogen from an organic matrix does not serve as a major pathway for N org elimination. Instead, we propose that hot H, O-containing fluids or some of their components gradually penetrate into the carbonaceous matrix and eliminate N org along a progressing reaction front, without causing nitrogen isotope fractionation in the residual N org in the unreacted core of the carbonaceous matrix. Before the reaction front can reach the core, an increasing part of core N org chemically stabilizes in the form of nitrogen atoms substituting for carbon in condensed, partially aromatic systems forming graphite-like structural domains with delocalized ?-electron systems (nitrogen atoms substituting for "graphitic" carbon in natural metamorphic organic matter). Thus, this nitrogen species with a conservative isotopic composition is the dominant form of residual nitrogen at higher metamorphic grade.

Boudou, Jean-Paul; Schimmelmann, Arndt; Ader, Magali; Mastalerz, Maria; Sebilo, Mathieu; Gengembre, Léon

2008-02-01

219

[50 years of clinical chemistry, first hand experience].  

PubMed

Approximately since 1945, progress in the field of photometric analysis also found its way into the laboratories of clinical chemistry. These techniques almost completely replaced the then prevailing gravimetric and titrimetric methods. At the same epoch, many of the biochemical reagents which up to then had to be prepared by the clinical laboratories themselves with great expenditure of work became commercially available. The increasing number of analytical orders could only be mastered thanks to the newly developed analyzers. Novel microliter techniques made it possible to diminish drastically the volumes of samples and reagents necessary. The radioimmunoassay opened up new analytical dimensions, the limits of detection and of quantification were expanded downwards to the picomol range. Soon afterwards, enzymes and/or fluorochromes were used as markers in immunoassays. The development of monoclonal antibodies constituted further important progress in this field. The latest revolutionary invention is doubtlessly the polymerase chain reaction (PCR), and related techniques. These methods are bound to bring about fundamental change not only in clinical chemistry but in the medical laboratory diagnostics in general. PMID:7770813

Keller, H

1995-05-01

220

The Big Picture: A Classroom Activity for Organic Chemistry  

ERIC Educational Resources Information Center

The new approach used for exploring new ways of enhancing experiences for students and instructors in science class is described. A fun activity conducted in the workshop for the observation of evolvement of group dynamics is discussed.

Poon, Thomas

2004-01-01

221

Surface chemistry of metal-organic frameworks at the liquid-solid interface.  

PubMed

Metal-organic frameworks (MOFs) are a fascinating class of novel inorganic-organic hybrid materials. They are essentially based on classic coordination chemistry and hold much promise for unique applications ranging from gas storage and separation to chemical sensing, catalysis, and drug release. The evolution of the full innovative potential of MOFs, in particular for nanotechnology and device integration, however requires a fundamental understanding of the formation process of MOFs. Also necessary is the ability to control the growth of thin MOF films and the positioning of size- and shape-selected crystals as well as MOF heterostructures on a given surface in a well-defined and oriented fashion. MOFs are solid-state materials typically formed by solvothermal reactions and their crystallization from the liquid phase involves the surface chemistry of their building blocks. This Review brings together various key aspects of the surface chemistry of MOFs. PMID:21190182

Zacher, Denise; Schmid, Rochus; Wöll, Christof; Fischer, Roland A

2011-01-01

222

Irreversible Organic Crystalline Chemistry Monitored in Real Time  

Microsoft Academic Search

Because multiple laser shots are typically required to monitor ultrafast photochemical reaction dynamics, sample depletion and product accumulation have greatly restricted the range of substrates and structural environments amenable to study. By implementing a two-dimensional spatial delay gradient across the profile of a femtosecond probe pulse, we can monitor in a single laser shot organic crystalline reaction dynamics despite the

Peter R. Poulin; Keith A. Nelson

2006-01-01

223

Observations of formic and acetic acid by chemical ionization mass spectrometry in the Deep Convective Clouds and Chemistry Experiment  

NASA Astrophysics Data System (ADS)

Formic (HFo) and acetic acid (HAc) are part of the atmospheric processing of carbon and their measurement is relevant to defining oxygenated volatile organic carbon (OVOC) emissions, to examining photochemical processing of volatile organic carbon (VOC) and OVOCs, and to the photochemical processing of organic aerosol. Further, they can serve as photochemical tracers of convective transport, cloud chemical processes, and precipitation scavenging. The addition of HFo and HAc measurements to the Deep Convective Clouds and Chemistry Experiment (DC3) is relevant to the DC3 science objectives and complements the suite of chemicals already observed during DC3. The peroxide chemical ionization mass spectrometer (PCIMS) was flown aboard the NCAR Gulfstream-V platform in DC3 and while its primary function was to observe hydrogen peroxide and methylhydroperoxide it recorded signals attributed to iodide cluster ions of HFo and HAc at mass-charge ratios of 173 and 187, respectively. Post-mission laboratory experiments were performed to determine the CIMS instrument's sensitivity to these acids under the varying water vapor and sample flow conditions encountered during DC3 flights. The results of field measurements, laboratory experiments and the HFo and HAc recovery process are reported and HFo and HAc measurement quality assessed. The resultant HFo and HAc data are presented and interpreted with respect to atmospheric chemistry within measurement constraints. The DC3 observations were made in May and June 2012 and extended from the surface to 13 km over the central United States.

Treadaway, V.; McNeill, A.; Heikes, B.; O'Sullivan, D. W.; Silwal, I.

2013-12-01

224

Size Exclusion Chromatography: An Experiment for High School and Community College Chemistry and Biotechnology Laboratory Programs  

ERIC Educational Resources Information Center

A simple multiday laboratory exercise suitable for use in a high school or community college chemistry course or a biotechnology advanced placement biology course is described. In this experiment students gain experience in the use of column chromatography as a tool for the separation and characterization of biomolecules, thus expanding their…

Brunauer, Linda S.; Davis, Kathryn K.

2008-01-01

225

Topics in Chemical Instrumentation: XCVIII. Experiments Involving Thermal Methods of Analysis for Undergraduate Chemistry Laboratories.  

ERIC Educational Resources Information Center

Explains some experiments involving thermal methods of analysis for undergraduate chemistry laboratories. Some experiments are: (1) the determination of the density and degree of crystallinity of a polymer; and (2) the determination of the specific heat of a nonvolatile compound. (HM)

Ewing, Galen W., Ed.

1978-01-01

226

Lysozyme Thermal Denaturation and Self-Interaction: Four Integrated Thermodynamic Experiments for the Physical Chemistry Laboratory  

ERIC Educational Resources Information Center

As part of an effort to infuse our physical chemistry laboratory with biologically relevant, investigative experiments, we detail four integrated thermodynamic experiments that characterize the denaturation (or unfolding) and self-interaction of hen egg white lysozyme as a function of pH and ionic strength. Students first use Protein Explorer to…

Schwinefus, Jeffrey J.; Schaefle, Nathaniel J.; Muth, Gregory W.; Miessler, Gary L.; Clark, Christopher A.

2008-01-01

227

An Enzymatic Clinical Chemistry Laboratory Experiment Incorporating an Introduction to Mathematical Method Comparison Techniques  

ERIC Educational Resources Information Center

An enzymatic laboratory experiment based on the analysis of serum is described that is suitable for students of clinical chemistry. The experiment incorporates an introduction to mathematical method-comparison techniques in which three different clinical glucose analysis methods are compared using linear regression and Bland-Altman difference…

Duxbury, Mark

2004-01-01

228

Ascorbic Acid as a Standard for Iodometric Titrations. An Analytical Experiment for General Chemistry  

Microsoft Academic Search

Ascorbic acid is suggested as the weighable compound for the standardization of iodine solutions in an analytical experiment in general chemistry. The experiment involves an iodometric titration in which iodine reacts with ascorbic acid, oxidizing it to dehydroascorbic acid. The redox titration endpoint is determined by the first iodine excess that is complexed with starch, giving a deep blue-violet color.

Cesar R. Silva; Jose A. Simoni; Carol H. Collins; Pedro L. O. Volpe

1999-01-01

229

PERSPECTIVE: From computational quantum chemistry to computational biology: experiments and computations are (full) partners  

Microsoft Academic Search

Computations are being integrated into biological research at an increasingly fast pace. This has not only changed the way in which biological information is managed; it has also changed the way in which experiments are planned in order to obtain information from nature. Can experiments and computations be full partners? Computational chemistry has expanded over the years, proceeding from computations

Buyong Ma; Ruth Nussinov

2004-01-01

230

Thai Undergraduate Chemistry Practical Learning Experiences Using the Jigsaw IV Method  

ERIC Educational Resources Information Center

The research reported in this study consisted of an investigation of student learning experiences in Thai chemistry laboratories using the Jigsaw IV method. A hands-on experiment based on the Jigsaw IV method using a real life example based on green tea beverage was designed to improve student affective variables for studying topics related to…

Jansoon, Ninna; Somsook, Ekasith; Coll, Richard K.

2008-01-01

231

Connecting Solubility, Equilibrium, and Periodicity in a Green, Inquiry Experiment for the General Chemistry Laboratory  

ERIC Educational Resources Information Center

We present a novel first-year chemistry laboratory experiment that connects solubility, equilibrium, and chemical periodicity concepts. It employs a unique format that asks students to replicate experiments described in different sample lab reports, each lacking some essential information, rather than follow a scripted procedure. This structure is…

Cacciatore, Kristen L.; Amado, Jose; Evans, Jason J.; Sevian, Hannah

2008-01-01

232

Shock-induced chemistry in simple organic molecules  

NASA Astrophysics Data System (ADS)

Interrogating chemical reactions behind a shock front is immensely difficult, and as a result, the details of shock-induced chemistry remain poorly understood. Shock compression creates transient distorted structures from which molecular reactions initiate. Previous works have reported that dimerizations, polymerizations, ring-opening and decomposition reactions occur under shock compression, depending on molecular structure. Certainly for explosives, exothermic decomposition reactions ultimately drive self-supported detonation. Questions regarding the thresholds for incipient reaction for different chemical functional groups, the nature of first and subsequent reaction steps, and the influence of shock input conditions on reaction kinetics remain to be answered. Evidence of reaction can be discerned from discontinuities in the mechanical variables for reactions with a change in density along the reaction coordinate, similar to first-order phase transformations. Here, we have applied in-situ electromagnetic gauging at multiple Lagrangian positions to elucidate the evolution of multiple-wave structures associated with shock-induced reactions. We have applied in-situ gauging, in concert with reactive molecular dynamic simulations, to investigate shock-reactivity of several simple functional groups: carbon-carbon double (-C=C-) and triple bonds, and nitriles (e.g. phenylacetylene and acrylonitrile), and aromatic ring structures (benzene), all building blocks for explosives. From measurements of the reactive flow, we have obtained detailed information about the temporal evolution of the waves, and global kinetics associated with transformation(s) between partially- and fully-reacted states. Near the reactive threshold, evolution in particle velocities point to reaction timescales on the order of several hundred nanoseconds. We have defined the reactive cusp Hugoniot states, and established the relative order of group reactivity under single shock conditions. These observations will be compared with reactions from the solid phase under static high pressure/temperature conditions, with a description of crystalline phase, and identification of polymerized products by in-situ x-ray diffraction and spectroscopic methods.

Dattelbaum, Dana

2011-06-01

233

Organic chemistry of graphene: the Diels-Alder reaction.  

PubMed

Herein, by using dispersion-corrected density functional theory, we investigated the Diels-Alder chemistry of pristine and defective graphene. Three dienes were considered, namely 2,3-dimethoxy-1,3-butadiene (DMBD), 9-methylanthracene (9MA), and 9,10-dimethylanthracene (910DMA). The dienophiles that were assayed were tetracyanoethylene (TCNE) and maleic anhydride (MA). When pristine graphene acted as the dienophile, we found that the cycloaddition products were 47-63?kcal?mol(-1) less stable than the reactants, thus making the reaction very difficult. The presence of Stone-Wales translocations, 585 double vacancies, or 555-777 reconstructed double vacancies did not significantly improve the reactivity because the cycloaddition products were still located at higher energy than the reactants. However, for the addition of 910DMA to single vacancies, the product showed comparable stability to the separated reactants, whereas for unsaturated armchair edges the reaction was extremely favorable. With regards the reactions with dienophiles, for TCNE, the cycloaddition product was metastable. In the case of MA, we observed a reaction product that was less stable than the reactants by 50?kcal?mol(-1) . For the reactions between graphene as a diene and the dienophiles, we found that the most-promising defects were single vacancies and unsaturated armchair edges, because the other three defects were much-less reactive. Thus, we conclude that the reactions with these above-mentioned dienes may proceed on pristine or defective sheets with heating, despite being endergonic. The same statement also applies to the dienophile maleic anhydride. However, for TCNE, the reaction is only likely to occur onto single vacancies or unsaturated armchair edges. We conclude that the dienophile character of graphene is slightly stronger than its behavior as a diene. PMID:24115199

Denis, Pablo A

2013-11-11

234

Results sections in sociology and organic chemistry articles: A genre analysis  

Microsoft Academic Search

This paper reports a genre study of the Results sections of two samples of 20 research-reporting articles from two disciplines: sociology and organic chemistry. Following the proposal of Bhatia (2004) that genre knowledge needs to be investigated from two perspectives, an ethnographic perspective and a textual perspective, the Results sections are analysed in terms of the social genre\\/cognitive genre model

Ian Bruce

2009-01-01

235

Results Sections in Sociology and Organic Chemistry Articles: A Genre Analysis  

ERIC Educational Resources Information Center

This paper reports a genre study of the Results sections of two samples of 20 research-reporting articles from two disciplines: sociology and organic chemistry. Following the proposal of Bhatia (2004) that genre knowledge needs to be investigated from two perspectives, an "ethnographic perspective" and a "textual perspective," the Results sections…

Bruce, Ian

2009-01-01

236

Using Biocatalysis to Integrate Organic Chemistry into a Molecular Biology Laboratory Course  

ERIC Educational Resources Information Center

Current cutting-edge biomedical investigation requires that the researcher have an operational understanding of several diverse disciplines. Biocatalysis is a field of science that operates at the crossroads of organic chemistry, biochemistry, microbiology, and molecular biology, and provides an excellent model for interdisciplinary research. We…

Beers, Mande; Archer, Crystal; Feske, Brent D.; Mateer, Scott C.

2012-01-01

237

Computer Based Instructional Techniques in Undergraduate Introductory Organic Chemistry: Rationale, Developmental Techniques, Programming Strategies and Evaluation.  

ERIC Educational Resources Information Center

Over 100 interactive computer programs for use in general and organic chemistry at the University of Texas at Austin have been prepared. The rationale for the programs is based upon the belief that computer-assisted instruction (CAI) can improve education by, among other things, freeing teachers from routine tasks, measuring entry skills,…

Culp, G. H.; And Others

238

Accidental Drowning or Foul Play?: A Case Study in Organic Chemistry  

ERIC Educational Resources Information Center

This case was developed for a sophomore organic chemistry lab to illustrate how a combination of techniques is usually required in the identification of chemical compounds. It involves a murder mystery with a forensic twist: Two bodies have been recovered from two different lakes, but because of a mix-up at the morgue, the coroner is unable to…

Konaklieva, Monika

2004-01-01

239

Stereoscopic Projection in Organic Chemistry: Bridging the Gap between Two and Three Dimensions.  

ERIC Educational Resources Information Center

Shows how to make stereo slides of three-dimensional molecular models. The slides have been used to teach chirality, conformational isomerism, how models and two-dimensional representations embody selected aspects of structure, and fundamentals of using the specific model set required in a particular organic chemistry course. (JN)

Rozzelle, Arlene A.; Rosenfeld, Stuart M.

1985-01-01

240

Grade/Study-Performance Contracts, Enhanced Communication, Cooperative Learning, and Student Performance in Undergraduate Organic Chemistry.  

ERIC Educational Resources Information Center

Describes and evaluates a teaching strategy, designed to increase student retention while maintaining academic performance levels in undergraduate organic chemistry, that uses grade/study-performance contracts, enhanced communication using electronic mail, and cooperative learning. Concludes that a series of interventions can substantially…

Dougherty, Ralph C.

1997-01-01

241

Using Green Chemistry Principles as a Framework to Incorporate Research into the Organic Laboratory Curriculum  

ERIC Educational Resources Information Center

Despite the accepted pedagogical value of integrating research into the laboratory curriculum, this approach has not been widely adopted. The activation barrier to this change is high, especially in organic chemistry, where a large number of students are required to take this course, special glassware or setups may be needed, and dangerous…

Lee, Nancy E.; Gurney, Rich; Soltzberg, Leonard

2014-01-01

242

Microwave-Assisted Chemistry: Synthetic Applications for Rapid Assembly of Nanomaterials and Organics  

EPA Science Inventory

The magic of microwave (MW) heating technique, termed as the Bunsen burner of the 21th Century, has emerged as valuable alternative in synthesis of organics, polymers, inorganics, and nanomaterials. Important innovations in MW-assisted chemistry now enable chemists to prepare cat...

243

Minimal Impact of Organic Chemistry Prerequisite on Student Performance in Introductory Biochemistry  

ERIC Educational Resources Information Center

Curriculum design assumes that successful completion of prerequisite courses will have a positive impact on student performance in courses that require the prerequisite. We recently had the opportunity to test this assumption concerning the relationship between completion of the organic chemistry prerequisite and performance in introductory…

Wright, Robin; Cotner, Sehoya; Winkel, Amy

2009-01-01

244

Incorporating Chemical Information Instruction and Environmental Science into the First-Year Organic Chemistry Laboratory  

ERIC Educational Resources Information Center

The chemical information instruction and environmental science which is incorporated into a first-year organic chemistry laboratory is presented. The students are charged with devised search strategies, conducting online searches and limiting the project scope to ocean systems. The laboratory serves to provide for search strategy development…

Landolt, R. G.

2006-01-01

245

Evaluation of Student Learning in Organic Chemistry Using the SOLO Taxonomy.  

ERIC Educational Resources Information Center

Describes the use of a standardized instrument, the Structure of Observed Learning Outcomes (SOLO) taxonomy, in an organic chemistry course at a small liberal arts college for women. Concludes that the method is a powerful tool for analyzing points of difficulty in student learning and following student progress in the understanding of particular…

Hodges, Linda C.; Harvey, Lilia C.

2003-01-01

246

Using the Cambridge Structural Database to Teach Molecular Geometry Concepts in Organic Chemistry  

ERIC Educational Resources Information Center

This article reports a set of two homework assignments that can be used in a second-year undergraduate organic chemistry class. These assignments were designed to help reinforce concepts of molecular geometry and to give students the opportunity to use a technological database and data mining to analyze experimentally determined chemical…

Wackerly, Jay Wm.; Janowicz, Philip A.; Ritchey, Joshua A.; Caruso, Mary M.; Elliott, Erin L.; Moore, Jeffrey S.

2009-01-01

247

Adapting to Student Learning Styles: Engaging Students with Cell Phone Technology in Organic Chemistry Instruction  

ERIC Educational Resources Information Center

Students of organic chemistry traditionally make 3 x 5 in. flash cards to assist learning nomenclature, structures, and reactions. Advances in educational technology have enabled flash cards to be viewed on computers, offering an endless array of drilling and feedback for students. The current generation of students is less inclined to use…

Pursell, David P.

2009-01-01

248

PAPER www.rsc.org/obc | Organic & Biomolecular Chemistry Synthesis and evaluation of caged Garcinia xanthones  

E-print Network

PAPER www.rsc.org/obc | Organic & Biomolecular Chemistry Synthesis and evaluation of caged Garcinia and potent bioactivities exhibited by several family members of the caged Garcinia xanthones, we developed pharmacophore. Introduction The Garcinia genus of tropical plants has yielded a structurally intriguing family

Theodorakis, Emmanuel

249

Neural Network Based on Quantum Chemistry for Predicting Melting Point of Organic Compounds  

Microsoft Academic Search

The melting points of organic compounds were estimated using a combined method that includes a backpropagation neural network and quantitative structure property relationship (QSPR) parameters in quantum chemistry. Eleven descriptors that reflect the intermolecular forces and molecular symmetry were used as input variables. QSPR parameters were calculated using molecular modeling and PM3 semi-empirical molecular orbital theories. A total of 260

Juan A. Lazzús

2009-01-01

250

The influence of microbial communities, management, and soil texture on soil organic matter chemistry  

E-print Network

, or labile C. Organic matter chemistry was determined before and after a 232-d incubation using pyrolysis gas chromatography/mass spectroscopy and microbial community properties were determined prior to incubation pool (r=0.65). Further, the three most abundant N-containing pyrolysis products, pyridine, pyrrole

Fierer, Noah

251

Emissions of volatile organic compounds from vegetation and the implications for atmospheric chemistry  

Microsoft Academic Search

Vegetation provides a major source of reactive carbon entering the atmosphere. These compounds play an important role in (1) shaping global tropospheric chemistry, (2) regional photochemical oxidant formation, (3) balancing the global carbon cycle, and (4) production of organic acids which contribute to acidic deposition in rural areas. Present estimates place the total annual global emission of these compounds between

Fred Fehsenfeld; Jack Calvert; Ray Fall; Paul Goldan; A. B. Guenther; C. N. Hewitt; Brian Lamb; Shaw Liu; Michael Trainer; Hal Westberg; Pat Zimmerman

1992-01-01

252

Assessment of Organic Chemistry Students' Knowledge of Resonance-Related Structures  

ERIC Educational Resources Information Center

This study examines how well second-year nonmajor organic chemistry students are learning to draw, interpret, and understand resonance-related structures. Students were tested seven times throughout an academic year using a set of four tasks that reflected their understanding of what these structures represent and how they relate to each other.…

Betancourt-Perez, Rosa; Olivera, Luis Javier; Rodriguez, Julio E.

2010-01-01

253

The chemistry and applications of metal-organic frameworks.  

PubMed

Crystalline metal-organic frameworks (MOFs) are formed by reticular synthesis, which creates strong bonds between inorganic and organic units. Careful selection of MOF constituents can yield crystals of ultrahigh porosity and high thermal and chemical stability. These characteristics allow the interior of MOFs to be chemically altered for use in gas separation, gas storage, and catalysis, among other applications. The precision commonly exercised in their chemical modification and the ability to expand their metrics without changing the underlying topology have not been achieved with other solids. MOFs whose chemical composition and shape of building units can be multiply varied within a particular structure already exist and may lead to materials that offer a synergistic combination of properties. PMID:23990564

Furukawa, Hiroyasu; Cordova, Kyle E; O'Keeffe, Michael; Yaghi, Omar M

2013-08-30

254

Some recent progress in the organic chemistry of water chlorination  

SciTech Connect

Research progress that has been recently in understanding the organic reactions occuring during low-level chlorination of natural waters is reviewed. Topics discussed are: humate materials: potential interactions with aqueous chlorine; effects of pH on reactivity of aqueous chlorine at low concentrations; natural phenolics as substrates for chlorine: haloform production; proteins as substrates for chlorine: production of carbon dioxide and haloacetonitriles, and depolymerization reactions.

Bean, R.M.

1981-11-01

255

Organic chemistry as a language and the implications of chemical linguistics for structural and retrosynthetic analyses.  

PubMed

Methods of computational linguistics are used to demonstrate that a natural language such as English and organic chemistry have the same structure in terms of the frequency of, respectively, text fragments and molecular fragments. This quantitative correspondence suggests that it is possible to extend the methods of computational corpus linguistics to the analysis of organic molecules. It is shown that within organic molecules bonds that have highest information content are the ones that 1)?define repeat/symmetry subunits and 2)?in asymmetric molecules, define the loci of potential retrosynthetic disconnections. Linguistics-based analysis appears well-suited to the analysis of complex structural and reactivity patterns within organic molecules. PMID:25044611

Cadeddu, Andrea; Wylie, Elizabeth K; Jurczak, Janusz; Wampler-Doty, Matthew; Grzybowski, Bartosz A

2014-07-28

256

The Titan Haze Simulation experiment: a laboratory study to explore the role of PAHs and PANHs in Titan's atmospheric chemistry  

NASA Astrophysics Data System (ADS)

A complex organic chemistry between Titan's two main constituents, N2 and CH4, leads to the production of more complex molecules and subsequently to solid organic aerosols. These aerosol particles form the haze layers giving Titan its characteristic orange color. In situ measurements by the Ion Neutral Mass Spectrometer (INMS) and Cassini Plasma Spectrometer (CAPS) instruments onboard Cassini have revealed the presence of large amounts of neutral, positively and negatively charged heavy molecules in the ionosphere of Titan[1,2]. In particular, benzene (C6H6) and toluene (C6H5CH3)[3], which are critical precursors of polycyclic aromatic hydrocarbon (PAH) compounds, have been detected, suggesting that PAHs might play a role in the production of Titan's aerosols. Moreover, results from numerical models[4,5] as well as laboratory simulations[6,7] of Titan's atmospheric chemistry are also suggesting chemical pathways that link the simple precursor molecules resulting from the first steps of the N2-CH4 chemistry (C2H2, C2H4, HCN...) to benzene, and to PAHs and nitrogen-containing PAHs (or PANHs) as precursors to the production of solid aerosols. The aim of the Titan Haze Simulation (THS) experiment is to study the chemical formation pathways, going from simple gas phase molecules to the more complex gas phase precursors of aerosols; and more specifically, to investigate the role of PAHs and PANHs in the nitrogen-methane enriched Titan atmosphere. In the THS experiment, Titan's atmospheric chemistry is simulated by a plasma jet expansion at pressure and temperature conditions close to those of Titan's atmosphere in the regions where aerosols are formed. The products of the chemistry are detected and studied using two complementary techniques: Cavity Ring Down Spectroscopy[8] and Time-Of-Flight Mass Spectrometry[9]. We will present the results of ongoing studies on different aspects of Titan's chemistry using various gas mixtures: from N2-CH4 gas mixtures at different CH4 concentrations to more targeted gas mixtures including trace elements present in Titan's atmosphere such as, for example, N2-C2H2, N2-C6H6 and N2-C2H2-C6H6 to study specific pathways to the production of PAHs and PANHs and large organic aerosols.

Sciamma-o'brien, E. M.; Contreras, C. S.; Ricketts, C. L.; Salama, F.

2011-12-01

257

Using Commercially Available Techniques to Make Organic Chemistry Representations Tactile and More Accessible to Students with Blindness or Low Vision  

ERIC Educational Resources Information Center

Organic chemistry courses can present major obstacles to access for students with blindness or low vision (BLV). In recent years, efforts have been made to represent organic chemistry concepts in tactile forms for blind students. These methodologies are described in this manuscript. Further work being done at Illinois State University is also…

Supalo, Cary A.; Kennedy, Sean H.

2014-01-01

258

The Determination of Ergosterol in Environmental Samples. An Interdisciplinary Project Involving Techniques of Analytical and Organic Chemistry  

NASA Astrophysics Data System (ADS)

In this undergraduate laboratory experiment, a naturally formed steroid that is an important environmental indicator of biological activity is extracted and quantified. The target compound is ergosterol, a steroid found only in fungi and an accepted measure of fungal biomass. Maple leaves were used as a representative sample, but the procedure can be extended to soils, fruits, and grains. The environmental sample is first saponified with methanolic KOH to release ergosterol from any bound forms. Next, the steroid is transferred into pentane to separate it from the polar components of the initial extract. After evaporation of the pentane, the residue containing the steroid is dissolved in methanol and filtered. This solution is analyzed on an HPLC instrument equipped with a reversed-phase column. Typical values for ergosterol in the maple leaf samples analyzed ranged from 22 to 240 mg/g of dry leaf. Leaves collected shortly after falling have low values, and those collected later have progressively higher values. The experiment has been tested in Analytical Chemistry, Environmental Chemistry, and Organic Chemistry classes and can be performed in two 3-hour laboratory periods.

Volker, Eugene J.; Dilella, Dan; Terneus, Kim; Baldwin, Carson; Volker, Ilona

2000-12-01

259

The Impacts of Marine Organic Emissions on Atmospheric Chemistry and Climate (Invited)  

NASA Astrophysics Data System (ADS)

Using laboratory studies and global/regional climate model results, this talk will contribute to two main research questions: 1) what can be learned about the carbon emission inducing stress factors for marine algae, and 2) what is a potential impact of marine biogenic volatile organic compound (VOC) emissions on global atmospheric chemistry and climate. Marine photosynthetic organisms emit VOCs which can form secondary organic aerosols (SOA). Currently large uncertainty exists in the magnitude of the marine biogenic sources, their spatiotemporal distribution, controlling factors, and contributions to natural background of organic aerosols. Here laboratory results for the production of isoprene and four monoterpene (?-pinene, ?-pinene, camphene and d-limonene) compounds as a function of variable light and temperature regimes for 6 different phytoplankton species will be discussed. The experiment was designed to simulate the regions where phytoplankton is subjected to changeable light/temperature conditions. The samples were grown and maintained at a climate controlled room. VOCs accumulated in the water and headspace above the water were measured by passing the sample through a gas chromatography/mass system equipped with a sample pre-concentrator allowing detection of low ppt levels of hydrocarbons. The VOC production rates were distinctly different for light/temperature stressed (the first 12 hour cycle at light/temperature levels higher than what the cultures were acclimated to in a climate controlled room) and photo/temperature-acclimated (the second 12 hour light/temperature cycle) states. In general, all phytoplankton species showed a rapid increase in isoprene and monoterpene production at higher light levels (between 150 to 420 ?E m-2 s-1) until a constant production rate was reached. Isoprene and ?-pinene, production rates also increased with temperature until a certain level, after which the rates declined as temperature increased further. Two modeling studies with the online emissions of marine isoprene/monoterpene and size-resolved marine primary organic aerosol have been carried out. The US EPA regional-scale Community Multiscale Air Quality modeling system was used to determine the impact of marine emissions on air quality, while the global-through-urban WRF/Chem model was applied to examine effect of ocean-derived trace gases and aerosols on chemistry-aerosol-cloud-climate interactions. With the isoprene reactions included in this study, the average contribution of marine isoprene to SOA and ozone (O3) concentrations is predicted to be small, up to 0.004 ?g m-3 for SOA and 0.2 ppb for O3 in coastal urban areas. When marine primary organic emissions are included, PM2.5 levels can be increased by 0.1-0.3 ?g m-3 (up to 5%) in some coastal cities such as San Francisco, CA. Regionally, marine organics (primary and secondary) can cause up to 20% increase in surface cloud condensation nuclei concentration. Global effects on cloud droplet number and indirect forcing are predicted to be small, less than 1 cm-3 and -0.1 W m-2, respectively.

Meskhidze, N.; Gantt, B.

2013-12-01

260

The Synthesis of 1-Phenyl-1,2,3,4-tetrahydroisoquinolines: An Undergraduate Organic Laboratory Experiment and Class Project.  

ERIC Educational Resources Information Center

Describes an undergraduate organic chemistry experiment (requiring three/four 3-hour laboratory sessions) involving a four-stage synthesis of 1-phenyl-1,2,3,4-tetrahydroisoquinolines via the Pictet-Spengler route. In addition, the experiment allows students to study the spectra and properties of aklaloid-like materials while completing several…

Letcher, R. M.; Sammes, M. P.

1985-01-01

261

The Kinetics of Photographic Development: A General Chemistry Experiment.  

ERIC Educational Resources Information Center

Student activities and experimental procedures are described for an experiment using black and white photographic development to illustrate the determination of reaction rate, kinetic order of a reactant, and activation energy. (Author/SK)

Byrd, J. E.; Perona, M. J.

1982-01-01

262

A Study of the Liquid-Liquid Partitioning Process Using Reverse-Phase Liquid Chromatography: An Undergraduate Analytical Chemistry Experiment.  

ERIC Educational Resources Information Center

Presents an undergraduate analytical chemistry experiment that promotes an interpretation of the molecular aspects of solute partitioning, enhancing student understanding of separation science and liquid chromatography. (CS)

Lochmuller, C. H.; And Others

1980-01-01

263

Laboratory Investigations Into The Origins Of Organic Chemistry  

NASA Astrophysics Data System (ADS)

The chain of chemical reactions leading towards life is thought to begin in molecular clouds when atomic carbon is fixed into molecules, initiating the synthesis of complex organic species. Spectroscopic observations, combined with sophisticated astrochemical models to interpret the collected spectra, provide much of our knowledge of this process. However, uncertainties in the underlying chemical data in these models limit our understanding of the molecular universe. Theory provides little insight as fully quantum mechanical calculations for reactions with four or more atoms are too complex for current capabilities. Measurements of rate coefficients for reactions of C with molecular ions are extremely challenging. This is due to the difficulty in producing a sufficiently intense and well characterized beam of neutral carbon atoms. We have developed a novel merged beam apparatus to study reactions of neutral atomic C with molecular ions. A C- beam is created in a cesium ion sputter source and accelerated to 28 keV. A series of apertures and electrostatic optics create a collimated beam. Using an 808 nm (1.53 eV) laser beam, ~4% of the C- beam is neutralized via photodetachment. We produce a pure ground term neutral C beam by electrostatically removing the remaining C-. A velocity matched, co-propagating H3+ beam at 7.05 keV, created with a duoplasmatron source, is then merged with the C beam. The merged beams method allows us to use fast beams, which are easy to handle and monitor, while being able to achieve relative collision energies down to some tens of meV. An electrostatic energy analyzer separates and detects the charged end products of the different reaction channels. The reactions rate coefficients are determined by measuring all the relevant currents, beam shapes, energies, signal counts and background rates. We have measured the absolute rate coefficients for C + H3+ ? CH+ + H2 and C + H3+ ? CH2+ + H. Since H3+ is ubiquitous in molecular clouds, these reactions are some of the first steps leading to the formation of complex organic molecules within such clouds. Our reaction studies will help to provide a better basis for astrochemical models and benchmarks for future theoretical development.

de Ruette, Nathalie; Miller, K. A.; O'Connor, A.; Stuetzel, J.; Urbain, X.; Savin, D. W.

2013-06-01

264

Eliciting Metacognitive Experiences and Reflection in a Year 11 Chemistry Classroom: An Activity Theory Perspective  

NASA Astrophysics Data System (ADS)

Concerns regarding students' learning and reasoning in chemistry classrooms are well documented. Students' reasoning in chemistry should be characterized by conscious consideration of chemical phenomenon from laboratory work at macroscopic, molecular/sub-micro and symbolic levels. Further, students should develop metacognition in relation to such ways of reasoning about chemistry phenomena. Classroom change eliciting metacognitive experiences and metacognitive reflection is necessary to shift entrenched views of teaching and learning in students. In this study, Activity Theory is used as the framework for interpreting changes to the rules/customs and tools of the activity systems of two different classes of students taught by the same teacher, Frances, who was teaching chemical equilibrium to those classes in consecutive years. An interpretive methodology involving multiple data sources was employed. Frances explicitly changed her pedagogy in the second year to direct students attention to increasingly consider chemical phenomena at the molecular/sub-micro level. Additionally, she asked students not to use the textbook until toward the end of the equilibrium unit and sought to engage them in using their prior knowledge of chemistry to understand their observations from experiments. Frances' changed pedagogy elicited metacognitive experiences and reflection in students and challenged them to reconsider their metacognitive beliefs about learning chemistry and how it might be achieved. While teacher change is essential for science education reform, students are not passive players in change efforts and they need to be convinced of the viability of teacher pedagogical change in the context of their goals, intentions, and beliefs.

Thomas, Gregory P.; McRobbie, Campbell J.

2013-06-01

265

Flow through reactors for organic chemistry: directly electrically heated tubular mini reactors as an enabling technology for organic synthesis.  

PubMed

Until recently traditional heating in organic chemistry has been done with oil heating baths or using electric heat exchangers. With the advent of microwave equipment, heating by microwaves was rapidly introduced as standard method in organic chemistry laboratories, mainly because of the convenient possibility to operate at high temperature accompanied by accelerated reaction rates. In the present contribution we discuss the method of heating small, continuously operated reactors by passing electric current directly through the reactor wall as an enabling technology in organic chemistry. The benefit of this method is that the heat is generated directly inside the reactor wall. By this means high heating rates comparable to microwave ovens can be reached but at much lower cost for the equipment. A tool for the comparison of microwave heating and traditional heating is provided. As an example kinetic data for the acid catalyzed hydrolysis of methyl formate were measured using this heating concept. The reaction is not only a suitable model but also one of industrial importance since this is the main production process for formic acid. PMID:20300506

Kunz, Ulrich; Turek, Thomas

2009-01-01

266

Flow through reactors for organic chemistry: directly electrically heated tubular mini reactors as an enabling technology for organic synthesis  

PubMed Central

Summary Until recently traditional heating in organic chemistry has been done with oil heating baths or using electric heat exchangers. With the advent of microwave equipment, heating by microwaves was rapidly introduced as standard method in organic chemistry laboratories, mainly because of the convenient possibility to operate at high temperature accompanied by accelerated reaction rates. In the present contribution we discuss the method of heating small, continuously operated reactors by passing electric current directly through the reactor wall as an enabling technology in organic chemistry. The benefit of this method is that the heat is generated directly inside the reactor wall. By this means high heating rates comparable to microwave ovens can be reached but at much lower cost for the equipment. A tool for the comparison of microwave heating and traditional heating is provided. As an example kinetic data for the acid catalyzed hydrolysis of methyl formate were measured using this heating concept. The reaction is not only a suitable model but also one of industrial importance since this is the main production process for formic acid. PMID:20300506

Turek, Thomas

2009-01-01

267

Cation Hydration Constants by Proton NMR: A Physical Chemistry Experiment.  

ERIC Educational Resources Information Center

Studies the polarization effect on water by cations and anions. Describes an experiment to illustrate the polarization effect of sodium, lithium, calcium, and strontium ions on the water molecule in the hydration spheres of the ions. Analysis is performed by proton NMR. (MVL)

Smith, Robert L.; And Others

1988-01-01

268

Enthalpy of Vaporization by Gas Chromatography: A Physical Chemistry Experiment  

ERIC Educational Resources Information Center

An experiment is conducted to measure the enthalpy of vaporization of volatile compounds like methylene chloride, carbon tetrachloride, and others by using gas chromatography. This physical property was measured using a very tiny quantity of sample revealing that it is possible to measure the enthalpies of two or more compounds at the same time.

Ellison, Herbert R.

2005-01-01

269

Foam Fractionation of Lycopene: An Undergraduate Chemistry Experiment  

ERIC Educational Resources Information Center

A novel experiment for the extraction of lycopene from tomato paste by foam fractionation is described. Foam fractionation is a process for separating and concentrating chemicals by utilizing differences in their surface activities. Extraction of lycopene by foam fractionation is a new method that has not been previously reported in the…

Wang, Yan; Zhang, Mingjie; Hu, Yongliang

2010-01-01

270

Chemical insights, explicit chemistry and yields of secondary organic aerosol from methylglyoxal and glyoxal  

NASA Astrophysics Data System (ADS)

Atmospherically abundant, volatile water soluble organic compounds formed through gas phase chemistry (e.g., glyoxal (C2), methylglyoxal (C3) and acetic acid) have great potential to form secondary organic aerosol (SOA) via aqueous chemistry in clouds, fogs and wet aerosols. This paper (1) provides chemical insights into aqueous-phase OH radical-initiated reactions leading to SOA formation from methylglyoxal and (2) uses this and a previously published glyoxal mechanism (Lim et al., 2010) to provide SOA yields for use in chemical transport models. Detailed reaction mechanisms including peroxy radical chemistry and a full kinetic model for aqueous photochemistry of acetic acid and methylglyoxal are developed and validated by comparing simulations with the experimental results from previous studies (Tan et al., 2010, 2012). This new methylglyoxal model is then combined with the previous glyoxal model (Lim et al., 2010), and is used to simulate the profiles of products and to estimate SOA yields. At cloud relevant concentrations (∼ 10-6-∼ 10-3 M; Munger et al., 1995) of glyoxal and methylglyoxal, the major photooxidation products are oxalic acid and pyruvic acid, and simulated SOA yields (by mass) are ∼ 120% for glyoxal and ∼ 80% for methylglyoxal. Oligomerization of unreacted aldehydes during droplet evaporation could enhance yields. In wet aerosols, where total dissolved organics are present at much higher concentrations (∼ 10 M), the major products are oligomers formed via organic radical-radical reactions, and simulated SOA yields (by mass) are ∼ 90% for both glyoxal and methylglyoxal.

Lim, Y. B.; Tan, Y.; Turpin, B. J.

2013-02-01

271

Redox chemistry and natural organic matter (NOM): Geochemists' dream, analytical chemists' nightmare  

USGS Publications Warehouse

Natural organic matter (NOM) is an inherently complex mixture of polyfunctional organic molecules. Because of their universality and chemical reversibility, oxidation/reductions (redox) reactions of NOM have an especially interesting and important role in geochemistry. Variabilities in NOM composition and chemistry make studies of its redox chemistry particularly challenging, and details of NOM-mediated redox reactions are only partially understood. This is in large part due to the analytical difficulties associated with NOM characterization and the wide range of reagents and experimental systems used to study NOM redox reactions. This chapter provides a summary of the ongoing efforts to provide a coherent comprehension of aqueous redox chemistry involving NOM and of techniques for chemical characterization of NOM. It also describes some attempts to confirm the roles of different structural moieties in redox reactions. In addition, we discuss some of the operational parameters used to describe NOM redox capacities and redox states, and describe nomenclature of NOM redox chemistry. Several relatively facile experimental methods applicable to predictions of the NOM redox activity and redox states of NOM samples are discussed, with special attention to the proposed use of fluorescence spectroscopy to predict relevant redox characteristics of NOM samples.

MacAlady, Donald L.; Walton-Day, Katherine

2011-01-01

272

The Most Beautiful Experiment in the History of Chemistry Sodium Ammonium Racemate  

E-print Network

The Most Beautiful Experiment in the History of Chemistry Sodium Ammonium Racemate Quartz ...These and brilliant discovery. On examining the crystals obtained in an attempt to form the double racemate of soda be modified in the same way, but always only [the same] four of them are facetted." Racemate: ..."as often

Walba, David

273

A Multi-Technique Forensic Experiment for a Nonscience-Major Chemistry Course  

ERIC Educational Resources Information Center

This multi-technique experiment with a forensic theme was developed for a nonscience-major chemistry course. The students are provided with solid samples and informed that the samples are either cocaine or a combination of drugs designed to mimic the stimulant and anesthetic qualities of cocaine such as caffeine and lidocaine. The students carry…

Szalay, Paul S.; Zook-Gerdau, Lois Anne; Schurter, Eric J.

2011-01-01

274

Coloring a Superabsorbent Polymer with Metal Ions: An Undergraduate Chemistry Experiment  

ERIC Educational Resources Information Center

A novel undergraduate chemistry experiment involving superabsorbent polymers commonly used in diapers and other personal care products is described. Students observe the removal of divalent transition-metal ions from aqueous solutions by the polymers. With the procedures provided, students are able to color the superabsorbent polymers with metal…

Yaung, Jing-Fun; Chen, Yueh-Huey

2009-01-01

275

Absorption and Scattering Coefficients: A Biophysical-Chemistry Experiment Using Reflectance Spectroscopy  

ERIC Educational Resources Information Center

A biophysical-chemistry experiment, based on the reflectance spectroscopy for calculating the absorption and scattering coefficients of leaves is described. The results show that different plants species exhibit different values for both the coefficients because of their different pigment composition.

Cordon, Gabriela B.; Lagorio, M. Gabriela

2007-01-01

276

A Practical and Convenient Diffusion Apparatus: An Undergraduate Physical Chemistry Experiment.  

ERIC Educational Resources Information Center

Described is a diffusion apparatus to be used in an undergraduate physical chemistry laboratory experiment to determine the diffusion coefficients of aqueous solutions of sucrose and potassium dichromate. Included is the principle of the method, apparatus design and description, and experimental procedure. (Author/DS)

Clifford, Ben; Ochiai, E. I.

1980-01-01

277

Molecular Orbitals of NO, NO[superscript+], and NO[superscript-]: A Computational Quantum Chemistry Experiment  

ERIC Educational Resources Information Center

This computational experiment presents qualitative molecular orbital (QMO) and computational quantum chemistry exercises of NO, NO[superscript+], and NO[superscript-]. Initially students explore several properties of the target molecules by Lewis diagrams and the QMO theory. Then, they compare qualitative conclusions with EHT and DFT calculations…

Orenha, Renato P.; Galembeck, Sérgio E.

2014-01-01

278

An Advanced Undergraduate Chemistry Laboratory Experiment Exploring NIR Spectroscopy and Chemometrics  

ERIC Educational Resources Information Center

An advanced undergraduate chemistry laboratory experiment to study the advantages and hazards of the coupling of NIR spectroscopy and chemometrics is described. The combination is commonly used for analysis and process control of various ingredients used in agriculture, petroleum and food products.

Wanke, Randall; Stauffer, Jennifer

2007-01-01

279

Determination of Mercury in Milk by Cold Vapor Atomic Fluorescence: A Green Analytical Chemistry Laboratory Experiment  

ERIC Educational Resources Information Center

Green analytical chemistry principles were introduced to undergraduate students in a laboratory experiment focused on determining the mercury concentration in cow and goat milk. In addition to traditional goals, such as accuracy, precision, sensitivity, and limits of detection in method selection and development, attention was paid to the…

Armenta, Sergio; de la Guardia, Miguel

2011-01-01

280

Application of Calibrated Peer Review (CPR) Writing Assignments to Enhance Experiments with an Environmental Chemistry Focus  

ERIC Educational Resources Information Center

The browser-based software program, Calibrated Peer Review (CPR) developed by the Molecular Science Project enables instructors to create structured writing assignments in which students learn by writing and reading for content. Though the CPR project covers only one experiment in general chemistry, it might provide lab instructors with a method…

Margerum, Lawrence D.; Gulsrud, Maren; Manlapez, Ronald; Rebong, Rachelle; Love, Austin

2007-01-01

281

An Environmental Chemistry Experiment: The Determination of Radon Levels in Water.  

ERIC Educational Resources Information Center

Describes a radiation experiment developed to complement a new environmental chemistry laboratory curriculum. A scintillation counter is used to measure radon in water. The procedure relies on the fact that toluene will preferentially extract radon from water. Sample preparation is complete in less than 90 minutes. Because the level of…

Welch, Lawrence E.; Mossman, Daniel M.

1994-01-01

282

THE MARS ENVIRONMENTAL COMPATIBILITY ASSESSMENT (MECA) WET CHEMISTRY EXPERIMENT ON THE MARS '01 LANDER  

E-print Network

THE MARS ENVIRONMENTAL COMPATIBILITY ASSESSMENT (MECA) WET CHEMISTRY EXPERIMENT ON THE MARS '01, Morgantown, WV, 26507 Introduction. The Mars Environmental Compatibility Assessment (MECA) is an instrument suite that will fly on the Mars Surveyor 2001 Lander Spacecraft. MECA is sponsored by the Human

Kounaves, Samuel P.

283

The 2001 Phoenix Sunrise experiment: vertical mixing and chemistry during the morning transition in Phoenix  

Microsoft Academic Search

A field experiment was carried out in Phoenix during June 2001 to examine the role of vertical mixing on the O3 chemistry of the boundary layer during the morning transition from stable to unstable atmospheric conditions. Surface instruments, instruments located on two floors of a 39 story building in downtown Phoenix, and an instrumented airplane were used to characterize the

J. C Doran; Carl M. Berkowitz; Richard L. Coulter; William J. Shaw; Chet W. Spicer

2003-01-01

284

Assessment of Antioxidant Capacities in Foods: A Research Experience for General Chemistry Students  

ERIC Educational Resources Information Center

With the booming interest in health food and nutrition, investigations of the antioxidant capacities of various foods have come to the forefront of food science. This general chemistry laboratory curriculum provides students with an opportunity to design and implement their own experiments relating to antioxidants in food. The curriculum is six…

Hoch, Matthew A.; Russell, Cianan B.; Steffen, Debora M.; Weaver, Gabriela C.; Burgess, John R.

2009-01-01

285

Emissions of volatile organic compounds from vegetation and the implications for atmospheric chemistry  

NASA Astrophysics Data System (ADS)

Vegetation provides a major source of reactive carbon entering the atmosphere. These compounds play an important role in (1) shaping global tropospheric chemistry, (2) regional photochemical oxidant formation, (3) balancing the global carbon cycle, and (4) production of organic acids which contribute to acidic deposition in rural areas. Present estimates place the total annual global emission of these compounds between approximately 500 and 825 Tg yr-1. The volatile olefinic compounds, such as isoprene and the monoterpenes, are thought to constitute the bulk of these emissions. However, it is becoming increasingly clear that a variety of partially oxidized hydrocarbons, principally alcohols, are also emitted. The available information concerning the terrestrial vegetation as sources of volatile organic compounds is reviewed. The biochemical processes associated with these emissions of the compounds and the atmospheric chemistry of the emitted compounds are discussed.

Fehsenfeld, Fred; Calvert, Jack; Fall, Ray; Goldan, Paul; Guenther, Alex B.; Hewitt, C. Nicholas; Lamb, Brian; Liu, Shaw; Trainer, Michael; Westberg, Hal; Zimmerman, Pat

1992-12-01

286

The Proceedings of the 53rd International Meeting of Physical Chemistry Organic Coatings  

SciTech Connect

These proceedings represent papers presented at the 53rd international meeting on physical chemistry held in Paris. The main topics discussed include theoretical and experimental aspects of adhesion, electrochemical techniques, plasma techniques, spin{minus}coating, coil{minus}coating, organosilane grafting and other techniques of film deposition, physicochemical characterization of films and interfaces and applications of organic coatings. There were 58 papers presented and all have been abstracted for the Energy Science and Technology database.(AIP)

Lacaze, P. [Institut de Topologie et de Dynamique des Systemes de l`Universite Paris 7-Denis Diderot, associe au CNRS,1,rue Guy de la Brosse, 75005 Paris (France)

1996-07-01

287

Grade/Performance Contracts, Enhanced Communication, Cooperative Learning and Student Performance in Undergraduate Organic Chemistry  

NASA Astrophysics Data System (ADS)

This paper describes a grade/study-performance contract that was designed to increase student retention while maintaining academic performance levels in undergraduate organic chemistry. The experimental course included enhanced communication using electronic mail, and cooperative learning in addition to grade/study-performance contracts. The objective of the grade/study-performance contract was the development of learning skills with creation of a basis for unobtrusive auditing of performance. The retention rate in the experimental course was 0.82 for the first term and 0.93 for the second term. The overall retention was 0.76. This value was 3.8 times the average retention for the same sequence in the previous five years at the same institution. It was seven standard deviations away from the previous mean. The ACS Organic Chemistry Examination percentile score for the control section was 46+25 (n=117). The corresponding data for the experimental section was 53+23 (n=143). When the course was offered with the same instructor, cooperative learning, e-mail, but no grade/study-performance contract the ACS Exam percentile average 37+29. This represents a drop of 9.9 standard deviations for comparison of the means. We conclude that grade/study-performance contracts can be effective in increasing both student performance and retention in undergraduate organic chemistry.

Dougherty, Ralph C.

1997-06-01

288

Becoming Organized: The Creativity of Organization, DisOrganization and ReOrganization in Scientific and Artistic Experiments  

Microsoft Academic Search

Taking its starting point from a recent experiment in the genetics of E. coli, this article explores how processes of organization, dis-organization and re-organization may be thought of as creative. Extending Deleuze and Guattari's concept of the Body without Organs and citing artworks such as George Legrady's Slippery Traces, Paul DeMarinis's Messenger, Jon McCormack's Eden and Natalie Jeremijenko's One Trees,

Timothy S. Barker

289

Becoming Organized: The Creativity of Organization, DisOrganization and ReOrganization in Scientific and Artistic Experiments  

Microsoft Academic Search

Taking its starting point from a recent experiment in the genetics of E. coli, this article explores how processes of organization, dis-organization and re-organization may be thought of as creative. Extending Deleuze and Guattari's concept of the Body without Organs and citing artworks such as George Legrady's Slippery Traces, Paul DeMarinis's Messenger, Jon McCormack's Eden and Natalie Jeremijenko's One Trees,

Timothy S. Barker; Isabelle Stengers; Carl Zimmer

2012-01-01

290

3D-printed devices for continuous-flow organic chemistry.  

PubMed

We present a study in which the versatility of 3D-printing is combined with the processing advantages of flow chemistry for the synthesis of organic compounds. Robust and inexpensive 3D-printed reactionware devices are easily connected using standard fittings resulting in complex, custom-made flow systems, including multiple reactors in a series with in-line, real-time analysis using an ATR-IR flow cell. As a proof of concept, we utilized two types of organic reactions, imine syntheses and imine reductions, to show how different reactor configurations and substrates give different products. PMID:23766811

Dragone, Vincenza; Sans, Victor; Rosnes, Mali H; Kitson, Philip J; Cronin, Leroy

2013-01-01

291

3D-printed devices for continuous-flow organic chemistry  

PubMed Central

Summary We present a study in which the versatility of 3D-printing is combined with the processing advantages of flow chemistry for the synthesis of organic compounds. Robust and inexpensive 3D-printed reactionware devices are easily connected using standard fittings resulting in complex, custom-made flow systems, including multiple reactors in a series with in-line, real-time analysis using an ATR-IR flow cell. As a proof of concept, we utilized two types of organic reactions, imine syntheses and imine reductions, to show how different reactor configurations and substrates give different products. PMID:23766811

Dragone, Vincenza; Sans, Victor; Rosnes, Mali H; Kitson, Philip J

2013-01-01

292

A Poster Session in Organic Chemistry That Markedly Enhanced Student Learning  

NASA Astrophysics Data System (ADS)

Chemistry courses worldwide have experienced dwindling student numbers and decreasing success rates in recent years. This has led to many proposals on ways to get students actively involved in their courses. At the University of the Witwatersrand, South Africa, our ChemII course has suffered a similar fate and the introduction of cooperative small group tutorials to get students actively involved in the learning process has met with limited success. Further innovations were introduced into the Organic II module, but students' perception of the module remained negative and their commitment to it has dwindled over the years. In the first semester of 1998 the ChemII class at Wits performed particularly poorly and only 23% of the students passed. In an attempt to improve this situation in the second semester, a poster presentation session was introduced into the Organic II module. The choice of topic for the poster was found to be crucial to the success of the innovation, which resulted in students' increased enthusiasm for, commitment to, and understanding of organic chemistry. Relative to the previous year, the class average for the Organic II module increased by 10% and the pass rate by 30% while the class average and pass rates in the other three ChemII modules (inorganic, analytical and physical) dropped by comparable amounts. This improvement in performance in the Organic II module is credited to the poster presentations shifting most students from a "futile learning cycle" into a "productive" one.

Huddle, P. A.

2000-09-01

293

Ralph F. Hirschmann award address 2009: Merger of organic chemistry with peptide diversity.  

PubMed

A huge unleashed potential lies hidden in the large and diverse pool of encoded and particularly nonencoded chiral alpha-, beta-, and gamma-amino acids available today. Although these have been extensively exploited in peptide science, the community of organic chemistry has only used this source of diversity in a quite focused and targeted manner. The properties and behavior of peptides as functional molecules in biology are well documented and based on the ability of peptides to adapt a range of discrete conformers at a minimal entropic penalty and therefore ideally fitting their endogenous targets. The development of new organic reactions and chemistries that in a general and quantitative way transform peptides into new functional molecules, preferably on solid support, is a source of completely new classes of molecules with important and advantageous functional properties. The peptide diversity and the ability to perform chemistry on solid support add tremendously to the combinatorial scope of such reactions in pharmaceutical and materials screening scenario. In recent years, the need for "click" reactions to shape complex molecular architecture has been realized mainly with a basis in the world of peptides and DNA, and in polymer chemistry where connection of highly functionalized biologically active substances or property bearing fragments are assembled as molecular LEGO using quantitative and orthogonal click chemistries. In this article, three such new reactions originating in the Carlsberg Laboratory over the last decade taking advantage of organic transformations in the peptide framework is presented. Initially, the click reaction between azide and terminal alkynes catalyzed by Cu(1) (CuAAC-reaction) is described. This CuAAC "click" reaction was observed first at Carlsberg Laboratory in reactions of azido acid chlorides with alkynes on solid support. Second, the Electrophilic Aromatic Substitution Cyclization-Intramolecular Click-Cascade (EASCy-ICC) reaction will be presented. This quantitative stereo-selective cascade reaction provides a highly diverse set of interesting novel scaffolds from peptides. Finally, we describe the preparation of solid phase peptide phosphine- and carbene-based green catalysts (organozymes), which upon complex formation with transition metal perform with high turnovers under aqueous conditions. These catalysts thrive from the peptide folding and diversity, while phosphines and carbenes in the backbone provide for bidental complex formation with transition metals in a format providing an excellent entry into combinatorial catalyst chemistry. PMID:20225304

Meldal, Morten; Tornøe, Christian W; Nielsen, Thomas E; Diness, Frederik; Le Quement, Sebastian T; Christensen, Christian A; Jensen, Jakob Feldthusen; Worm-Leonhard, Kasper; Groth, Thomas; Bouakaz, Lamine; Wu, Boqian; Hagel, Grith; Keinicke, Lise

2010-01-01

294

Research and Teaching: A Performance Enhanced Interactive Learning Workshop Model as a Supplement for Organic Chemistry Instruction  

NSDL National Science Digital Library

In this study, the authors describe a Performance Enhanced Interactive Learning (PEIL) workshop model as a supplement for organic chemistry instruction. This workshop model differs from many others in that it includes public presentations by students and

Grose-Fifer, Jilliam; Phillips, Karen E.

2011-01-01

295

Thalidomide Makes a Comeback: A Case Discussion Exercise That Integrates Biochemistry and Organic Chemistry  

NASA Astrophysics Data System (ADS)

The case discussion method, which involves teaching scientific theory in a framework that students can relate to their own world, is an interdisciplinary pedagogical tool. Therefore, case study exercises can be used to integrate biochemistry with other advanced chemistry courses. The case presented here can be used at the end of a second-semester organic chemistry course or in an introductory biochemistry course. The case is a fact-based, fictional story in which an FDA official must decide whether to carry out the agency's threat to shut down several buyers clubs that import thalidomide from overseas and dispense it to their members for the treatment of AIDS. Students are required to read the body of the case, analyze data, and search for information using limited leads. Using well-considered arguments based on their research, they are asked to come to conclusions about how the element of risk involved in thalidomide distribution is assessed. They apply their knowledge of biochemistry to assess how thalidomide acts at the cellular level and they apply their knowledge of organic chemistry in writing mechanisms of thalidomide hydrolysis and in the design of thalidomide analogs. Students are assessed on their ability to work in groups, to critically analyze scientific data, and to develop public policies based on risk-benefit analysis.

Bennett, Nicole; Cornely, Kathleen

2001-06-01

296

Organic Chemistry: Radioactive Carbohydrates, Sugars in Solution, Aldol Condensations, Molecular Structure, Synthesis of Selected Compounds, Air Polution Studies, Reference Materials (Organic) July 1964 to June 1965.  

National Technical Information Service (NTIS)

The report describes work in progress in the Organic Chemistry Section at the National Bureau of Standards on the following subjects: Synthesis of carbon-14- and tritium-labeled carbohydrates, isotope dilution and double-lavel methods of analysis, determi...

H. S. Isbell

1965-01-01

297

The surface as molecular reagent: organic chemistry at the semiconductor interface  

NASA Astrophysics Data System (ADS)

Methods for the incorporation of organic functionality onto semiconductor surfaces have seen immense progress in recent years. Of the multiple methods developed, the direct, covalent attachment of organic moieties is valuable because it allows for excellent control of the interfacial properties. This review article will focus on a number of synthetic strategies that have been developed to exploit the unique reactivity of group-IV surfaces under vacuum. A picture of the semiconductor surface and its reactions will be developed within the standard framework of organic chemistry with emphasis on the importance of combined experimental and theoretical approaches. Three broad areas of organic chemistry will be highlighted, including nucleophilic/electrophilic, pericyclic, and aromatic reactions. The concept of nucleophilicity and electrophilicity will be discussed within the context of dative bonding and proton transfer of amines and alcohols. Pericyclic reactions cover the [4 + 2] or Diels-Alder cycloaddition, [2 + 2] cycloaddition, dipolar, and ene reactions. Examples include the reactions of alkenes, dienes, ketones, nitriles, and related multifunctional molecules at the interface. Aromaticity and the use of directing groups to influence the distribution of surface products will be illustrated with benzene, xylene, and heteroaromatic compounds. Finally, multifunctional molecules are used to describe the competition and selectively observed among different surface reactions.

Filler, Michael A.; Bent, Stacey F.

2003-09-01

298

Seasonal Carbonate Chemistry Covariation with Temperature, Oxygen, and Salinity in a Fjord Estuary: Implications for the Design of Ocean Acidification Experiments  

PubMed Central

Carbonate chemistry variability is often poorly characterized in coastal regions and patterns of covariation with other biologically important variables such as temperature, oxygen concentration, and salinity are rarely evaluated. This absence of information hampers the design and interpretation of ocean acidification experiments that aim to characterize biological responses to future pCO2 levels relative to contemporary conditions. Here, we analyzed a large carbonate chemistry data set from Puget Sound, a fjord estuary on the U.S. west coast, and included measurements from three seasons (winter, summer, and fall). pCO2 exceeded the 2008–2011 mean atmospheric level (392 µatm) at all depths and seasons sampled except for the near-surface waters (< 10 m) in the summer. Further, undersaturated conditions with respect to the biogenic carbonate mineral aragonite were widespread (?ar<1). We show that pCO2 values were relatively uniform throughout the water column and across regions in winter, enriched in subsurface waters in summer, and in the fall some values exceeded 2500 µatm in near-surface waters. Carbonate chemistry covaried to differing levels with temperature and oxygen depending primarily on season and secondarily on region. Salinity, which varied little (27 to 31), was weakly correlated with carbonate chemistry. We illustrate potential high-frequency changes in carbonate chemistry, temperature, and oxygen conditions experienced simultaneously by organisms in Puget Sound that undergo diel vertical migrations under present-day conditions. We used simple calculations to estimate future pCO2 and ?ar values experienced by diel vertical migrators based on an increase in atmospheric CO2. Given the potential for non-linear interactions between pCO2 and other abiotic variables on physiological and ecological processes, our results provide a basis for identifying control conditions in ocean acidification experiments for this region, but also highlight the wide range of carbonate chemistry conditions organisms may currently experience in this and similar coastal ecosystems. PMID:24586915

Reum, Jonathan C. P.; Alin, Simone R.; Feely, Richard A.; Newton, Jan; Warner, Mark; McElhany, Paul

2014-01-01

299

Fostering Pre-service Teachers' Self-Determined Environmental Motivation Through Green Chemistry Experiments  

NASA Astrophysics Data System (ADS)

The global environmental crisis intensifies particularly in developing nations. Environmental educators have begun to understand that changing the environmental impact requires not only changes in pro-environmental knowledge and attitudes but also in associated, self-determined motivation. This study was designed to test the hypothesis that a green chemistry curriculum changes Malaysian pre-service teachers' environmental motivation. Two comparable groups of pre-service teachers participated in this study. The students in the experimental group ( N = 140) did green chemistry experiments whereas the control group ( N = 123) did equivalent experiments in a traditional manner. Posttest results indicate that there is significant difference between both the groups for intrinsic motivation, integration, identification, and introjections scales and no differences for external regulation and amotivation scales. The qualitative analysis of interview data suggests that the changes are predominantly due to the personal satisfaction that participants derived from engaging in pro-environmental behavior.

Karpudewan, Mageswary; Ismail, Zurida; Roth, Wolff-Michael

2012-10-01

300

Change in student conceptual and technological knowledge as a result of the general chemistry laboratory experience  

NASA Astrophysics Data System (ADS)

The use of technology is continually changing within the field of chemistry and is increasingly being incorporated into teaching laboratories under the supposition that technology makes concepts more understandable. General chemistry students at South Dakota State University use computer-based laboratory technology weekly during data collection, analysis, and final submission of their laboratory reports. The purpose of this study was to assess the impact of technology on student learning. Qualitative and quantitative methods were used to analyze this impact. Surveys, observations, and interviews were used to collect data as students completed experiments during the general chemistry laboratory. Chi-square analysis determined that changes between pre- and post-survey data were statistically significant. A qualitative index (q) was used to assess which laboratory experiments had smaller or larger changes in student knowledge. Evidence of positive and negative changes in student conceptual and technological knowledge will be coupled to the various laboratory technology used by general chemistry laboratory students, including the Chem 2000, thermocouples, and the pH electrode. Data show that students initially were focused on learning the technology and that students re-directed their focus to learning laboratory concepts as the academic year progressed. Data show that the level of engagement students were at and their use of the visuals provided by the laboratory technology affected their learning. Data show that students emphasized collecting accurate and precise data in the laboratory and associated the technology with providing them with accurate and precise data. Data also shows the relationship between the lecture and laboratory portions of the general chemistry courses has no impact on student learning. Evidence of these impacts on student learning will be presented.

Williams, Marla F.

301

A Model for Tropospheric Multiphase Chemistry: Application to One Cloudy Event During the CIME Experiment  

Microsoft Academic Search

In this study, we have used a multiphase box model which takes into account an explicit chemistry mechanism for both gas and\\u000a aqueous phase for a rural environment and the kinetic of mass transfer between phases (Schwartz, 1986). The model is, then,\\u000a initialized with multiphase measurements performed by Voisin et al. (2000) during the CIME experiment. The 13th December 1997,

M. Leriche; D. Voisin; N. Chaumerliac; A. Monod

302

Explicit modeling of organic chemistry and secondary organic aerosol partitioning for Mexico City and its outflow plume  

SciTech Connect

The evolution of organic aerosols (OA) in Mexico City and its outflow is investigated with the nearly explicit gas phase photochemistry model GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere), wherein precursor hydrocarbons are oxidized to numerous intermediate species for which vapor pressures are computed and used to determine gas/particle partitioning in a chemical box model. Precursor emissions included observed C3-10 alkanes, alkenes, and light aromatics, as well as larger n-alkanes (up to C25) not directly observed but estimated by scaling to particulate emissions according to their volatility. Conditions were selected for comparison with observations made in March 2006 (MILAGRO). The model successfully reproduces the magnitude and diurnal shape for both primary (POA) and secondary (SOA) organic aerosols, with POA peaking in the early morning at 15-20 ug m-3, and SOA peaking at 10-15 ?g m-3 during mid-day. The majority (> 75%) of the model SOA stems from the large n-alkanes, with the remainder mostly from the light aromatics. Simulated OA elemental composition reproduces observed H/C and O/C ratios reasonably well, although modeled ratios develop more slowly than observations suggest. SOA chemical composition is initially dominated by *- hydroxy ketones and nitrates from the large alkanes, with contributions from peroxy acyl nitrates and, at later times when NOx is lower, organic hydroperoxides. The simulated plume-integrated OA mass continues to increase for several days downwind despite dilution-induced particle evaporation, since oxidation chemistry leading to SOA formation remains strong. In this model, the plume SOA burden several days downwind exceeds that leaving the city by a factor of >3. These results suggest significant regional radiative impacts of SOA.

Lee-Taylor, J.; Madronich, Sasha; Aumont, B.; Baker, A.; Camredon, M.; Hodzic, Alma; Tyndall, G. S.; Apel, Eric; Zaveri, Rahul A.

2011-12-21

303

Supramolecular chemistry: from molecular information towards self-organization and complex matter  

Microsoft Academic Search

Molecular chemistry has developed a wide range of very powerful procedures for constructing ever more sophisticated molecules from atoms linked by covalent bonds. Beyond molecular chemistry lies supramolecular chemistry, which aims at developing highly complex chemical systems from components interacting via non-covalent intermolecular forces. By the appropriate manipulation of these interactions, supramolecular chemistry became progressively the chemistry of molecular information,

Jean-Marie Lehn

2004-01-01

304

Introduction to Homogenous Catalysis with Ruthenium-Catalyzed Oxidation of Alcohols: An Experiment for Undergraduate Advanced Inorganic Chemistry Students  

ERIC Educational Resources Information Center

A three-week laboratory experiment, which introduces students in an advanced inorganic chemistry course to air-sensitive chemistry and catalysis, is described. During the first week, the students synthesize RuCl[subscript 2](PPh[subscript 3])[subscript 3]. During the second and third weeks, the students characterize the formed coordination…

Miecznikowski, John R.; Caradonna, John P.; Foley, Kathleen M.; Kwiecien, Daniel J.; Lisi, George P.; Martinez, Anthony M.

2011-01-01

305

A Fifty-Year Love Affair with Organic Chemistry (by William S. Johnson)  

NASA Astrophysics Data System (ADS)

This latest volume is the 20th in Jeff Seeman's projected 22-volume series of autobiographies of 20th-century organic chemists that began publication in 1990 (Kauffman, G. B. J. Chem. Educ. 1991, 68, A21). Unfortunately, Johnson did not live to see this volume in print. Ted Bartlett and Ray Conrow reviewed the final manuscript, galleys, and page proofs; and Ted Bartlett, Paul Bartlett, John D. Roberts, and Gilbert Stork contributed an epilogue that complements Johnson's own words, adds a warm, personal final touch that he was unable to provide, and incorporates his final research into the volume. Born in New Rochelle, New York, on February 24, 1913, William Summer Johnson attended Amherst College with the aid of a scholarship and various odd jobs such as tending furnace, washing dishes, and playing saxophone in dance bands (he seriously considered becoming a professional musician). Here he became enamored with organic chemistry, which he taught as an instructor for a year after his graduation magna cum laude in 1936. He then worked with a fellowship under Louis Fieser, who sparked his interest in steroids, at Harvard University, from which he received his M.A. (1938) and Ph.D. (1940) degrees. In 1940 Johnson joined the faculty at the University of Wisconsin, where he rose through the ranks, eventually becoming Homer Adkins Professor of Chemistry (1954-60). He began the total synthesis of steroids, the main subject of his life's work, "which soon proved to be the hottest synthetic target of the time". In 1960 he accepted an invitation to become head of and to upgrade the Stanford University Chemistry Department. With faculty recruiting as his primary concern, he was able to add Carl Djerassi, Paul J. Flory, Harden M. McConnell, Henry Taube, and Eugene E. van Tamelen to the department, resulting in its spectacular rise from 15th to 5th place in the nation. He remained at Stanford for the rest of his career, serving as department head for nine years. He died at the age of 82 on August 19, 1995. Johnson's book reads like a Who's Who of Organic Chemistry, with descriptions, impressions, and thumbnail sketches of such luminaries as Sir Robert Robinson, Robert B. Woodward, Gilbert Stork, Carl Djerassi, Derek Barton, John D. ("Jack") Roberts, and authors of other Profiles volumes. During his long and productive career, Johnson made many contributions to contemporary organic chemistry, the genesis and course of which he describes lucidly with extensive use of 110 structural formulas, 75 reaction schemes, and occasional laboratory notebook pages. Three hundred fifty-six graduate and undergraduate students, postdocs, and visiting professors (many of whom are shown in the 63 formal and informal photographs in the book) have worked with him through five and a half decades. In "Some Concluding Remarks about Our Research", Johnson states, "The reviewed research did not evolve from a master plan; indeed it was largely a matter of following one's nose and trying to look at things that related to areas that were regarded as important issues of the time." Johnson's intimate and revealing autobiography will not only appeal to synthetic organic chemists but will be of interest to both present and future generations of students and instructors of chemistry courses and the history of science as well as to all persons concerned with the human aspects of science.

Kauffman, Reviewed By George B.; Kauffman, Laurie M.

1999-12-01

306

Data Pooling in a Chemical Kinetics Experiment: The Aquation of a Series of Cobalt(III) Complexes--A Discovery Chemistry Experiment  

ERIC Educational Resources Information Center

An experiment in chemical kinetics as part of our Discovery Chemistry curriculum is described. Discovery Chemistry is a pedagogical philosophy that makes the laboratory the key center of learning for students in their first two years of undergraduate instruction. Questions are posed in the pre-laboratory discussion and assessed using pooled…

Herrick, Richard S.; Mills, Kenneth V.; Nestor, Lisa P.

2008-01-01

307

A Series of Synthetic Organic Experiments Demonstrating Physical Organic Principles.  

ERIC Educational Resources Information Center

Describes several common synthetic organic transformations involving alkenes, alcohols, alkyl halides, and ketones. Includes concepts on kinetic versus thermodynamic control of reaction, rearrangement of a secondary carbocation to a tertiary cation, and the effect of the size of the base on orientation during elimination. (MVL)

Sayed, Yousry; And Others

1989-01-01

308

Chemistry Notes.  

ERIC Educational Resources Information Center

Presents background information, laboratory procedures, classroom materials/activities, and experiments for chemistry. Topics include superheavy elements, polarizing power and chemistry of alkali metals, particulate carbon from combustion, tips for the chemistry laboratory, interesting/colorful experiments, behavior of bismuth (III) iodine, and…

School Science Review, 1982

1982-01-01

309

Organic Aerosol Formation in the Humid, Photochemically-Active Southeastern US: SOAS Experiments and Simulations  

NASA Astrophysics Data System (ADS)

Aqueous multiphase chemistry in the atmosphere can lead to rapid transformation of organic compounds, forming highly oxidized low volatility organic aerosol and, in some cases, light absorbing (brown) carbon. Because liquid water is globally abundant, this chemistry could substantially impact climate, air quality, health, and the environment. Gas-phase precursors released from biogenic and anthropogenic sources are oxidized and fragmented forming water-soluble gases that can undergo reactions in the aqueous phase (in clouds, fogs, and wet aerosols) leading to the formation of secondary organic aerosol (SOAAQ). Recent studies have highlighted the role of certain precursors like glyoxal, methylglyoxal, glycolaldehyde, acetic acid, acetone, and epoxides in the formation of SOAAQ. The goal of this work is to identify other precursors that are atmospherically important. In this study, ambient mixtures of water-soluble gases were scrubbed from the atmosphere at Brent, Alabama during the Southern Oxidant and Aerosol Study (SOAS). Four mist chambers in parallel collected ambient gases in a DI water medium at 20-25 LPM with a 4 hr collection time. Total organic carbon (TOC) values in daily composited samples were 64-180 ?M. Aqueous OH radical oxidation experiments were conducted with these mixtures in a newly designed cuvette chamber to understand the formation of SOA through gas followed by aqueous chemistry. OH radicals (3.5E-2 ?M [OH] s-1) were formed in-situ in the chamber, continuously by H2O2 photolysis. Precursors and products of these aqueous OH experiments were characterized using ion chromatography (IC), electrospray ionization mass spectrometry (ESI-MS), and IC-ESI-MS. ESI-MS results from a June 12th, 2013 sample showed precursors to be primarily odd, positive mode ions, indicative of the presence of non-nitrogen containing alcohols, aldehydes, organic peroxides, or epoxides. Products were seen in the negative mode and included organic acid ions like pyruvate and oxalate. The results from this study will be used to better understand aqueous chemistry in clouds/fogs and to identify precursors for laboratory study of wet aerosol, fog, and cloud chemistry.

Sareen, N.; Lim, Y. B.; Carlton, A. G.; Turpin, B. J.

2013-12-01

310

State-of-the-Art-Symposium: Self-Organization in Chemistry.  

ERIC Educational Resources Information Center

Presents four articles dealing with chaotic systems. Lists sources for nine demonstrations or experiments dealing with self-organization. Provides a vocabulary review of self-organization. Describes three chemical oscillator models. Discusses the role of chaos in flow systems. (MVL)

Soltzberg, Leonard J.; And Others

1989-01-01

311

Stereochemical Control in Carbohydrate Chemistry  

ERIC Educational Resources Information Center

Carbohydrates, in the form of glycoconjugates, have recently been shown to control a wide range of cellular processes. Accordingly, students interested in the study of organic chemistry and biomedical sciences should be exposed to carbohydrate chemistry. To this end, we have developed a sequence of experiments that leads the student from the…

Batchelor, Rhys; Northcote, Peter T.; Harvey, Joanne E.; Dangerfield, Emma M.; Stocker, Bridget L.

2008-01-01

312

Measurement of the Order Parameter in a Room Temperature Liquid Crystal: An Experiment for the Physical Chemistry Laboratory.  

ERIC Educational Resources Information Center

Presented here is a laboratory experiment for a course in physical chemistry. Students are requested to directly measure the degree of orientational order in a liquid crystal at room temperature. A minimum amount of equipment is necessary. (Author/SA)

DuPre, Donald B.; Chapoy, L. Lawrence

1979-01-01

313

Chemistry Notes  

ERIC Educational Resources Information Center

Described are eight chemistry experiments and demonstrations applicable to introductory chemistry courses. Activities include: measure of lattice enthalpy, Le Chatelier's principle, decarboxylation of soap, use of pocket calculators in pH measurement, and making nylon. (SL)

School Science Review, 1976

1976-01-01

314

Chemistry Notes.  

ERIC Educational Resources Information Center

Presents background information, laboratory procedures, classroom materials/activities, and chemistry experiments. Topics include sublimation, electronegativity, electrolysis, experimental aspects of strontianite, halide test, evaluation of present and future computer programs in chemistry, formula building, care of glass/saturated calomel…

School Science Review, 1983

1983-01-01

315

Pollution Prevention Plan for the Y-12 Analytical Chemistry Organization Off-Site Union Valley Facility  

SciTech Connect

The Y-12 Analytical Chemistry Organization (ACO) Off-Site Union Valley Facility (Union Valley Facility) is managed by Babcock and Wilcox Technical Services Y-12, L.L.C. (B and W Y-12) through the Y-12 National Security Complex organization. Accordingly, the Y-12 Pollution Prevention Program encompasses the operations conducted at the Union Valley Facility. The Y-12 Program is designed to fully comply with state, federal and U.S. Department of Energy (DOE) requirements concerning waste minimization/pollution prevention as documented in the Y-12 Pollution Prevention Program Plan. The Program is formulated to reduce the generation and toxicity of all Y-12 wastes in all media, including those wastes generated by the Union Valley Facility operations. All regulatory and DOE requirements are met by the Y-12 Program Plan.

Jackson, J. G.

2010-03-01

316

Neural Network Based on Quantum Chemistry for Predicting Melting Point of Organic Compounds  

NASA Astrophysics Data System (ADS)

The melting points of organic compounds were estimated using a combined method that includes a backpropagation neural network and quantitative structure property relationship (QSPR) parameters in quantum chemistry. Eleven descriptors that reflect the intermolecular forces and molecular symmetry were used as input variables. QSPR parameters were calculated using molecular modeling and PM3 semi-empirical molecular orbital theories. A total of 260 compounds were used to train the network, which was developed using MatLab. Then, the melting points of 73 other compounds were predicted and results were compared to experimental data from the literature. The study shows that the chosen artificial neural network and the quantitative structure property relationships method present an excellent alternative for the estimation of the melting point of an organic compound, with average absolute deviation of 5%.

Lazzús, Juan A.

2009-02-01

317

Distinct Optical Chemistry of Dissolved Organic Matter in Urban Pond Ecosystems  

PubMed Central

Urbanization has the potential to dramatically alter the biogeochemistry of receiving freshwater ecosystems. We examined the optical chemistry of dissolved organic matter (DOM) in forty-five urban ponds across southern Ontario, Canada to examine whether optical characteristics in these relatively new ecosystems are distinct from other freshwater systems. Dissolved organic carbon (DOC) concentrations ranged from 2 to 16 mg C L-1 across the ponds with an average value of 5.3 mg C L-1. Excitation-emission matrix (EEM) spectroscopy and parallel factor analysis (PARAFAC) modelling showed urban pond DOM to be characterized by microbial-like and, less importantly, by terrestrial derived humic-like components. The relatively transparent, non-humic DOM in urban ponds was more similar to that found in open water, lake ecosystems than to rivers or wetlands. After irradiation equivalent to 1.7 days of natural solar radiation, DOC concentrations, on average, decreased by 38% and UV absorbance decreased by 25%. Irradiation decreased the relative abundances of terrestrial humic-like components and increased protein-like aspects of the DOM pool. These findings suggest that high internal production and/or prolonged exposure to sunlight exerts a distinct and significant influence on the chemistry of urban pond DOM, which likely reduces its chemical similarity with upstream sources. These properties of urban pond DOM may alter its biogeochemical role in these relatively novel aquatic ecosystems. PMID:24348908

McEnroe, Nicola A.; Williams, Clayton J.; Xenopoulos, Marguerite A.; Porcal, Petr; Frost, Paul C.

2013-01-01

318

Enhancing the Student Experiment Experience: Visible Scientific Inquiry Through a Virtual Chemistry Laboratory  

NASA Astrophysics Data System (ADS)

Practical work is often noted as a core reason many students take on science in secondary schools (high schools). However, there are inherent difficulties associated with classroom practical work that militate against scientific inquiry, an approach espoused by many science educators. The use of interactive simulations to facilitate student inquiry has emerged as a complement to practical work. This study presents case studies of four science teachers using a virtual chemistry laboratory (VCL) with their students in an explicitly guided inquiry manner. Research tools included the use of the Inquiry Science Implementation Scale in a `talk-aloud' manner, Reformed Teaching Observation Protocol for video observations, and teacher interviews. The findings suggest key aspects of practical work that hinder teachers in adequately supporting inquiry and highlight where a VCL can overcome many of these difficulties. The findings also indicate considerations in using the VCL in its own right.

Donnelly, Dermot; O'Reilly, John; McGarr, Oliver

2013-08-01

319

Organizing a Community Advanced Pharmacy Practice Experience  

PubMed Central

Setting up a community advanced pharmacy practice experience can be an overwhelming task for many pharmacy preceptors. This article provides guidance to pharmacist preceptors in developing a complete and effective community advanced pharmacy practice experience (APPE). When preparing for the APPE, initial discussions with the college or school of pharmacy are key. Benefits, training, and requirements should be addressed. Site preparation, including staff education, will assist in the development process. The preceptor should plan orientation day activities and determine appropriate evaluation and feedback methods. With thorough preparation, the APPE will be rewarding for both the student and the pharmacy site. PMID:17136163

Koenigsfeld, Carrie Foust; Tice, Angela L

2006-01-01

320

The Effect of Organic Compounds in Pot Experiments.  

E-print Network

DIVISION OF VETERINARY SCIENCE M. FRANCIS, D. V. S., Veterinarian in Charge H. ScHMIDT, D. V . M ., Assistant Veter inarian DIVISION OF CHEMISTRY G. S. FRAPS, Ph. D., Chemist in Charge: Stale Chemist J . W. CHEWNING, B. S., Assistant Chemist R. H... by the usual methods employed by us. The quantity of soil contained in these pots was not always the same. In the earlier experiments there was from 5000 to 6000 gi'ams of soil, but in later experiments the quantity of soil taken was uniformly 5000 grams...

Fraps, G. S.

1915-01-01

321

Chemistry Links  

NSDL National Science Digital Library

This compiled site contains titles and links to over 40 sites, journal articles, course and tutorial materials, simulations, batteries, and other resources. Definitions of chemistry, theoretical chemistry, organic, physical and nuclear chemistry are integrated with the links to outside materials. A number of useful keywords are included to help users navigate the materials.

Charnine, Michael

2011-04-01

322

Oxygenated Organic Chemicals in the Pacific Troposphere: Distribution, Sources and Chemistry  

NASA Technical Reports Server (NTRS)

Airborne measurements of a large number of oxygenated organic chemicals (Oxorgs) were carried out in the Pacific troposphere (0.1-12 km) in the Spring of 2001 (Feb. 24-April 10). Specifically these measuremen ts included acetone, methylethyl ketone (MEK), methanol, ethanol, ace taldehyde, propionaldehyde, PANS, and organic nitrates. Complementary measurements of formaldehyde, organic peroxides, and tracers were al so available. Ox-orgs were abundant in the clean troposphere and were greatly enhanced in the outflow regions from Asia. Their mixing ratios were typically highest in the lower troposphere and declined toward s the upper troposphere and the lowermost stratosphere. Their total a bundance (Ox-orgs) significantly exceeded that of NMHC (C2-C8 NMHC). A comparison of these data with observations collected some seven yea rs earlier (Feb.-March, 1994), did not reveal any significant changes . Throughout the troposphere mixing ratios of Ox-orgs were strongly c orrelated with each other as well as with tracers of fossil and bioma sshiof'uel combustion. Analysis of the relative enhancement of selected Oxorgs with respect to CH3Cl and CO in twelve sampled plumes, origi nating from fires, is used to assess their primary and secondary sour ces from biomass combustion. The composition of these plumes also ind icates a large shift of reactive nitrogen into the PAN reservoir ther eby limiting ozone formation. The Harvard 3-D photochemical model, th at uses state of the art chemistry and source information, is used to compare simulated and observed mixing ratios of selected species. A 1 -D model is used to explore the chemistry of aldehydes. These results will be presented.

Singh, Hanwant B.; Salas, L.; Chatfield, R.; Czech, E.; Fried, A.; Evans, M.; Jacob, D. J.; Blake, D.; Heikes, B.; Talbot, R.

2003-01-01

323

Intrinsic charge trapping in organic and polymeric semiconductors: a physical chemistry perspective  

SciTech Connect

We aim to understand the origins of intrinsic charge carrier traps in organic and polymeric semiconductor materials from a physical chemistry perspective. In crystalline organic semiconductors, we point out some of the inadequacies in the description of intrinsic charge traps using language and concepts developed for inorganic semiconductors. In ?-conjugated polymeric semiconductors, we suggest the presence of a two-tier electronic energy landscape, a bimodal majority landscape due to two dominant structural motifs and a minority electronic energy landscape from intrinsic charged defects. The bimodal majority electronic energy landscape results from a combination of amorphous domains and microcrystalline or liquid-crystalline domains. The minority tier of the electronic density of states is comprised of deep Coulomb traps embedded in the majority electronic energy landscape. This minority electronic energy landscape may dominate transport properties at low charge carrier densities, such as those expected for organic photovoltaic devices, while the bimodal majority electronic energy landscape becomes significant at high carrier densities, that is, in organic field effect transistors.

Zhu, Xiaoyang; Barbara, Paul F.; Kaake, Loren

2010-01-01

324

Ascorbic Acid as a Standard for Iodometric Titrations. An Analytical Experiment for General Chemistry  

NASA Astrophysics Data System (ADS)

Ascorbic acid is suggested as the weighable compound for the standardization of iodine solutions in an analytical experiment in general chemistry. The experiment involves an iodometric titration in which iodine reacts with ascorbic acid, oxidizing it to dehydroascorbic acid. The redox titration endpoint is determined by the first iodine excess that is complexed with starch, giving a deep blue-violet color. The results of the titration of iodine solution using ascorbic acid as a calibration standard were compared with the results acquired by the classic method using a standardized solution of sodium thiosulfate. The standardization of the iodine solution using ascorbic acid was accurate and precise, with the advantages of saving time and avoiding mistakes due to solution preparation. The colorless ascorbic acid solution gives a very clear and sharp titration end point with starch. It was shown by thermogravimetric analysis that ascorbic acid can be dried at 393 K for 2 h without decomposition. This experiment allows general chemistry students to perform an iodometric titration during a single laboratory period, determining with precision the content of vitamin C in pharmaceutical formulations.

Silva, Cesar R.; Simoni, Jose A.; Collins, Carol H.; Volpe, Pedro L. O.

1999-10-01

325

Global tropospheric experiment at the Hong Kong Atmosphere Chemistry Measurement Station  

NASA Technical Reports Server (NTRS)

The major activities of the Global Tropospheric Experiment at the Hong Kong Atmospheric Chemistry Measurement Station are presented for the period 1 January - 31 December 1995. Activities included data analysis, reduction, and archiving of atmospheric measurements and sampling. Sampling included O3, CO, SO2, NO, TSP, RSP, and ozone column density. A data archive was created for the surface meteorological data. Exploratory data analysis was performed, including examination of time series, frequency distributions, diurnal variations and correlation. The major results have been or will be published in scientific journals as well as presented at conferences/workshops. Abstracts are attached.

Carroll, Mary Ann; Wang, Tao

1995-01-01

326

Molecular Chemistry of Organic Aerosols Through the Application of High Resolution Mass Spectrometry  

SciTech Connect

Understanding of molecular composition and fundamental chemical transformations of organic aerosols (OA) during their formation and aging is both a major challenge and the area of greatest uncertainty in atmospheric research. Particularly little is known about fundamental relationship between the chemical composition and physicochemical properties of OA, their atmospheric history, evolution, and impact on the environment. Ambient soft-ionization methods combined with high-resolution mass spectrometry (HR-MS) analysis provide detailed information on the molecular content of OA that is pivotal for improved understanding of their complex composition, multi-phase aging chemistry, direct (light absorption and scattering) and indirect (aerosol-cloud interactions) effects on atmospheric radiation and climate, and health effects. The HR-MS methods can detect thousands of individual OA constituents at once, provide their elemental formulae from accurate mass measurements, and provide structural information based on tandem mass spectrometry. Integration with additional analytical tools, such as chromatography and UV/Vis absorption spectroscopy, makes it possible to further separate OA compounds by their polarity and ability to absorb solar radiation. The goal of this perspective is to describe modern HR-MS methods, review recent applications to field and laboratory studies of OA, and explain how the information obtained from HR-MS methods can be translated into improved understanding of OA chemistry.

Nizkorodov, Serguei; Laskin, Julia; Laskin, Alexander

2011-01-05

327

The PROCESS experiment: an astrochemistry laboratory for solid and gaseous organic samples in low-earth orbit.  

PubMed

The PROCESS (PRebiotic Organic ChEmistry on the Space Station) experiment was part of the EXPOSE-E payload outside the European Columbus module of the International Space Station from February 2008 to August 2009. During this interval, organic samples were exposed to space conditions to simulate their evolution in various astrophysical environments. The samples used represent organic species related to the evolution of organic matter on the small bodies of the Solar System (carbonaceous asteroids and comets), the photolysis of methane in the atmosphere of Titan, and the search for organic matter at the surface of Mars. This paper describes the hardware developed for this experiment as well as the results for the glycine solid-phase samples and the gas-phase samples that were used with regard to the atmosphere of Titan. Lessons learned from this experiment are also presented for future low-Earth orbit astrochemistry investigations. PMID:22680688

Cottin, Hervé; Guan, Yuan Yong; Noblet, Audrey; Poch, Olivier; Saiagh, Kafila; Cloix, Mégane; Macari, Frédérique; Jérome, Murielle; Coll, Patrice; Raulin, François; Stalport, Fabien; Szopa, Cyril; Bertrand, Marylène; Chabin, Annie; Westall, Frances; Chaput, Didier; Demets, René; Brack, André

2012-05-01

328

Distributed Pore Chemistry in Porous Organic Polymers in Tissue Culture Flasks  

NASA Technical Reports Server (NTRS)

A method for making a biocompatible polymer article using a uniform atomic oxygen treatment is disclose. The substrate may be subsequently optionally grated with a compatibilizing compound. Compatibilizing compounds may include proteins, phosphorylcholine groups, platelet adhesion preventing polymers, albumin adhesion promoters, and the like. The compatibilized substrate may also have a living cell layer adhered thereto. The atomic oxygen is preferably produced by a flowing afterglow microwave discharge, wherein the substrate resides in a sidearm out of the plasma. Also, methods for culturing cells for various purposes using the various membranes are disclosed as well. Also disclosed are porous organic polymers having a distributed pore chemistry (DPC) comprising hydrophilic and hydrophobic regions, and a method for making the DPC by exposing the polymer to atomic oxygen wherein the rate of hydrophilization is greater than the rate of mass loss.

Koontz, Steven L. (Inventor)

1999-01-01

329

In situ experiment of ontogenetic variability in the otolith chemistry of Stegastes partitus  

Microsoft Academic Search

Otolith chemistry can be used to assess pelagic larval fish connectivity by comparing spatially variable otolith edge chemistry (corresponding to the site of collection) to otolith core chemistry (corresponding to the site of hatching). However, because the otolith’s edge and core represent different life stages, the deposition of elements may differ, thus complicating direct comparisons of edge and core chemistry

P. M. Chittaro; J. D. Hogan; J. Gagnon; B. J. Fryer; P. F. Sale

2006-01-01

330

A personal recollection of Ernest Roy Davidson's contributions to organic chemistry  

NASA Astrophysics Data System (ADS)

Ernest Davidson's contributions of potential energy surfaces for thermal reactions of organic compounds form an important body of scientific work. His pursuit, with Borden, of the methylenecyclopropane degenerate rearrangement involving the trimethylenemethane singlet biradical with planar and orthogonal species is a classic example that also touches on the Davidson-Borden characterization of open shell, pi conjugated biradicals as either disjoint or non-disjoint systems. In a related effort with vinylmethylenecyclopropane he not only calculated all reasonable stationary points for both the singlet and triplet species, but demonstrated the preference for a conrotatory-bevel closure of a cross-conjugated 1,5 singlet biradical. Further, he pursued the classic hydrocarbon 1,3 biradicals trimethylene and vinyltrimethylene, showing in the latter case that there are no intermediates on the potential energy surface. Thus the reaction appears to proceed from saddle point to saddle point by traversing coordinates perpendicular to the reaction coordinates. He became embroiled in the Cope rearrangement energy surface that pushed the limits of approximations to the solution of the Schroedinger equation. He provided evidence that the conservation of orbital symmetry 'forbidden' suprafacial-inversion 1,5 shift of carbon in the circumambulatory degenerate rearrangement of norcaradiene is comparable in energy with the 'allowed' suprafacial-retention pathway. And he provided important insights into the captodative effects of monoradicals. Ernest understands more organic chemistry than most organic chemists.

Gajewski, Joseph J.

331

Major Successes of Theory-and-Experiment-Combined Studies in Surface Chemistry and Heterogeneous Catalysis.  

SciTech Connect

Experimental discoveries followed by theoretical interpretations that pave the way of further advances by experimentalists is a developing pattern in modern surface chemistry and catalysis. The revolution of modern surface science started with the development of surface-sensitive techniques such as LEED, XPS, AES, ISS and SIMS, in which the close collaboration between experimentalists and theorists led to the quantitative determination of surface structure and composition. The experimental discovery of the chemical activity of surface defects and the trends in the reactivity of transitional metals followed by the explanations from the theoretical studies led to the molecular level understanding of active sites in catalysis. The molecular level knowledge, in turn, provided a guide for experiments to search for new generation of catalysts. These and many other examples of successes in experiment-and-theory-combined studies demonstrate the importance of the collaboration between experimentalists and theorists in the development of modern surface science.

Somorjai, Gabor A.; Li, Yimin

2009-11-21

332

Experiment Results Microspectroscopy of Meteorites: Search for Organic Mineral Correlations  

E-print Network

Experiment Results Microspectroscopy of Meteorites: Search for Organic ­ Mineral Correlations M-Milwaukee, Milwaukee, WI, 53211 Introduction * myesiltas @ knights.ucf.edu Organic molecules in meteorites can that coalesced to form meteorite source objects. The amount and type of such molecules created may depend

Peale, Robert E.

333

The Construction of Metal-Organic Framework with Active Backbones by the Utilization of Reticular Chemistry  

NASA Astrophysics Data System (ADS)

With the principles of reticular chemistry, metal-organic frameworks with ultra-high porosity, chiral-recognition unit as a chiral stationary phase, metalloporhyrins for enhanced hydrogen adsorption and an intrinsic conductivity to form porous conductors, have been prepared. This dissertation presents how the principles of reticular chemistry were utilized to achieve in the preparations of metal-organic frameworks with a large surface area and active backbones. Through the simple isoreticular (having the same framework topology) expansion from MOF-177 composed with 1,3,5-tris(4'-carboxyphenyl-)benzene (BTB3-) as the strut; MOF-200 was prepared with 4,4',4"-(benzene-1,3,5-triyl-tris(benzene-4,1-diy1))tribenzoic acid an extension from BTB3- by a phenylene unit to yield one of the most porous MOFs with a Langmuir surface area of 10,400 m2. and the lowest density of 0.22 cm3.g-1. A successful thermal polymerization reaction at 325 °C inside of the pores of highly porous MOF, MOF-177, was performed and verified the integrity of the MOF structure even after the thermal reaction. 1,4-Diphenylbutadiyne that is known to polymerize upon heating to form a conjugated backbone was impregnated via solution-diffusion into MOF-177 and then subsequently polymerized by heat to form polymer impregnated MOF-177. Characterization was carried out using powder X-ray diffraction and volumetric sorption analyzer. MOF-1020 with a linear quaterphenyl dicarboxylate-based strut was designed to contain a chiral bisbinaphthyl crown-ether moiety for alkyl ammonium resolution was precisely placed into a Zn4O(CO2)6-based cubic MOF structure. Unfortunately, the chiral resolution was not achieved due to the sensitivity and the pore environment of MOF-1020. However, an interesting phenomenon was observed, where the loss of crystallinity occurs upon solvent removal while the crystallites remain shiny and crystalline, but it readily is restored upon re-solvation of the crystallites. This rare phenomenon was studied by powder X-ray diffraction and supported by gas adsorption and thermogravimetric analysis. Layered MOFs with metalloporphyrins with Zn, Cu, Co and Fe at their +2 oxidation states as struts were prepared to facilitate non-structural metal sites and tested for hydrogen adsorption and the binding enthalpies. Steep uptakes are indeed observed, but rather due to the optimal interlayer distance of 9 A for dihydrogen, and the binding enthalpies are 6.7 -- 7.6 kJ . mo1-1 which are not ·extraordinary. Although the metals did not seem to play a large role, a trend was observed where the binding enthalpies increase as the metals in the metalloporphyrins go from late to early transition metals. With the concept of conductive metal oxides, a journey of constructing conductive MOFs was taken by attempting the formation of metal-carbon bonds by linking transition metal ions with conjugated organic struts which are 1,4-benzenediisonitrile, 1,4-benzenediethynylide and p-cyanophenylethynylide. Among the attempted systems, a reaction of Cr(III) and 1,4-benzenediethynylide yielded an amorphous material with a BET (Brunauer-Emmett-Teller) surface area of 80 m2.g-1, hydrogen uptake of 47 cm 3. g-1 and a resistance of 20 MO. Also a crystalline compound was prepared by mimicking Prussian blue by using p-cyanophenylethynylide where one end can bind metal with ethynylic carbon and the other end with the cyano nitrogen by following the similar synthesis of Prussian blue analogues. The principles of reticular chemistry are demonstrated through each chapter and show how powerful and beneficial reticular chemistry is by allowing the predetermination of the structure and function. The details of the ways to approach an ideal compound and the synthetic aspects are also described in this dissertation.

Choi, Eunwoo

334

Doing Chemistry  

NSDL National Science Digital Library

This website includes over 150 chemistry experiments in the following areas: Atomic Structure, Bonding, Chemical Reactions, Colligative Properties, Condensed States, Electrochemistry, Equilibrium Gases, Instrumentation, Limiting Reactant and more.

Brooks, David W.

2010-05-25

335

Observations of peroxyacetyl nitrate (PAN) in the upper troposphere by the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS)  

NASA Astrophysics Data System (ADS)

Peroxyacetyl nitrate (CH3CO·O2NO2, abbreviated as PAN) is a trace molecular species present in the troposphere and lower stratosphere due primarily to pollution from fuel combustion and the pyrogenic outflows from biomass burning. In the lower troposphere, PAN has a relatively short life-time and is principally destroyed within a few hours through thermolysis, but it can act as a reservoir and carrier of NOx in the colder temperatures of the upper troposphere where UV photolysis becomes the dominant loss mechanism. Pyroconvective updrafts from large biomass burning events can inject PAN into the upper troposphere and lower stratosphere (UTLS), providing a means for the long-range transport of NOx. Given the extended lifetimes at these higher altitudes, PAN is readily detectable via satellite remote sensing. A new PAN data product is now available for the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) Version 3.0 data set. We report measurements of PAN in Boreal biomass burning plumes recorded during the Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS) campaign. The retrieval method employed and errors analysis are described in full detail. The retrieved volume mixing ratio (VMR) profiles are compared to coincident measurements made by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument on the European Space Agency (ESA) ENVIronmental SATellite (ENVISAT). Three ACE-FTS occultations containing measurements of Boreal biomass burning outflows, recorded during BORTAS, were identified as having coincident measurements with MIPAS. In each case, the MIPAS measurements demonstrated good agreement with the ACE-FTS VMR profiles for PAN. The ACE-FTS PAN data set is used to obtain zonal mean distributions of seasonal averages from ~5 to 20 km. A strong seasonality is clearly observed for PAN concentrations in the global UTLS. Since the principal source of PAN in the UTLS is due to lofted biomass burning emissions from the pyroconvective updrafts created by large fires, the observed seasonality in enhanced PAN coincides with fire activity in different geographical regions throughout the year. This work is part of an in-depth investigation that is being conducted in an effort to study the aging and chemical evolution of biomass burning emissions in the UTLS by remote, space-borne measurements made by ACE-FTS to further our understanding of the impact of pyrogenic emissions on atmospheric chemistry. Included in this study will be the addition of new, pyrogenic, volatile organic hydrocarbons (VOCs) and oxygenated volatile organic compounds (OVOCs) to expand upon the already extensive suite of molecules retrieved by ACE-FTS to aid in elucidating biomass burning plume chemistry in the free troposphere.

Tereszchuk, K. A.; Moore, D. P.; Harrison, J. J.; Boone, C. D.; Park, M.; Remedios, J. J.; Randel, W. J.; Bernath, P. F.

2013-01-01

336

Adhesion of bacterial pathogens to soil colloidal particles: influences of cell type, natural organic matter, and solution chemistry.  

PubMed

Bacterial adhesion to granular soil particles is well studied; however, pathogen interactions with naturally occurring colloidal particles (<2 ?m) in soil has not been investigated. This study was developed to identify the interaction mechanisms between model bacterial pathogens and soil colloids as a function of cell type, natural organic matter (NOM), and solution chemistry. Specifically, batch adhesion experiments were conducted using NOM-present, NOM-stripped soil colloids, Streptococcus suis SC05 and Escherichia coli WH09 over a wide range of solution pH (4.0-9.0) and ionic strength (IS, 1-100 mM KCl). Cell characterization techniques, Freundlich isotherm, and Derjaguin-Landau-Verwey-Overbeek (DLVO) theory (sphere-sphere model) were utilized to quantitatively determine the interactions between cells and colloids. The adhesion coefficients (Kf) of S. suis SC05 to NOM-present and NOM-stripped soil colloids were significantly higher than E. coli WH09, respectively. Similarly, Kf values of S. suis SC05 and E. coli WH09 adhesion to NOM-stripped soil colloids were greater than those colloids with NOM-present, respectively, suggesting NOM inhibits bacterial adhesion. Cell adhesion to soil colloids declined with increasing pH and enhanced with rising IS (1-50 mM). Interaction energy calculations indicate these adhesion trends can be explained by DLVO-type forces, with S. suis SC05 and E. coli WH09 being weakly adhered in shallow secondary energy minima via polymer bridging and charge heterogeneity. S. suis SC05 adhesion decreased at higher IS 100 mM, which is attributed to the change of hydrophobic effect and steric repulsion resulted from the greater presence of extracellular polymeric substances (EPS) on S. suis SC05 surface as compared to E. coli WH09. Hence, pathogen adhesion to the colloidal material is determined by a combination of DLVO, charge heterogeneity, hydrophobic and polymer interactions as a function of solution chemistry. PMID:24495985

Zhao, Wenqiang; Walker, Sharon L; Huang, Qiaoyun; Cai, Peng

2014-04-15

337

Synthesis and Hydrogenation of Disubstituted Chalcones: A Guided-Inquiry Organic Chemistry Project  

ERIC Educational Resources Information Center

Guided-inquiry experiments offer the same opportunities to participate in the process of science as classical organic qualitative analysis used to do. This three-week guided-inquiry project involves an aldol-dehydration synthesis of a chalcone chosen from a set of nine, followed by a catalytic transfer hydrogenation reaction using ammonium formate…

Mohrig, Jerry R.; Hammond, Christina Noring; Schatz, Paul F.; Davidson, Tammy A.

2009-01-01

338

Synthesis of Well-Defined Copper "N"-Heterocyclic Carbene Complexes and Their Use as Catalysts for a "Click Reaction": A Multistep Experiment that Emphasizes the Role of Catalysis in Green Chemistry  

ERIC Educational Resources Information Center

A multistep experiment for an advanced synthesis lab course that incorporates topics in organic-inorganic synthesis and catalysis and highlights green chemistry principles was developed. Students synthesized two "N"-heterocyclic carbene ligands, used them to prepare two well-defined copper(I) complexes and subsequently utilized the complexes as…

Ison, Elon A.; Ison, Ana

2012-01-01

339

Incrementally Approaching an Inquiry Lab Curriculum: Can Changing a Single Laboratory Experiment Improve Student Performance in General Chemistry?  

ERIC Educational Resources Information Center

Many institutions are responding to current research about how students learn science by transforming their general chemistry laboratory curricula to be inquiry-oriented. We present a comparison study of student performance after completing either a traditional or an inquiry stoichiometry experiment. This single laboratory experience was the only…

Cacciatore, Kristen L.; Sevian, Hannah

2009-01-01

340

Characterization of High Explosives and Other Energetic Compounds by Computational Chemistry and Molecular Modeling: Experiments for Undergraduate Curriculum  

ERIC Educational Resources Information Center

Experiments suited for the undergraduate instructional laboratory in which the heats of formation of several aliphatic and aromatic compounds are calculated, are described. The experiments could be used to introduce students to commercially available computational chemistry and its thermodynamics, while assess and compare the energy content of…

Bumpus, John A.; Lewis, Anne; Stotts, Corey; Cramer, Christopher J.

2007-01-01

341

Electronic Transitions as a Probe of Tetrahedral versus Octahedral Coordination in Nickel(II) Complexes: An Undergraduate Inorganic Chemistry Experiment.  

ERIC Educational Resources Information Center

Discusses procedures, theoretical considerations, and results of an experiment involving the preparation of a tetrahedral nickel(II) complex and its transformation into an octahedral species. Suggests that fundamental aspects of coordination chemistry can be demonstrated by simple experiments performed in introductory level courses. (Author/JN)

Filgueiras, Carlos A. L.; Carazza, Fernando

1980-01-01

342

Chemistry Rocks: Redox Chemistry as a Geologic Tool.  

ERIC Educational Resources Information Center

Applies chemistry to earth science, uses rocks in chemistry laboratories, and teaches about transition metal chemistry, oxidation states, and oxidation-reduction reactions from firsthand experiences. (YDS)

Burns, Mary Sue

2001-01-01

343

Gender Fair Efficacy of Concept Mapping Tests in Identifying Students' Difficulties in High School Organic Chemistry  

ERIC Educational Resources Information Center

In view of the perceived difficulty of organic chemistry unit for high schools students, this study examined the usefulness of concept mapping as a testing device to assess students' difficulty in the select areas. Since many tests used for identifying students misconceptions and difficulties in school subjects are observed to favour one or…

Gafoor, Kunnathodi Abdul; Shilna, V.

2014-01-01

344

The Cyclohexanol Cycle and Synthesis of Nylon 6,6: Green Chemistry in the Undergraduate Organic Laboratory  

ERIC Educational Resources Information Center

A one-term synthesis project that incorporates many of the principles of green chemistry is presented for the undergraduate organic laboratory. In this multistep scheme of reactions, students react, recycle, and ultimately convert cyclohexanol to nylon 6,6. The individual reactions in the project employ environmentally friendly methodologies, and…

Dintzner, Matthew R.; Kinzie, Charles R.; Pulkrabek, Kimberly; Arena, Anthony F.

2012-01-01

345

Bridging the gap between cell biology and organic chemistry: chemical synthesis and biological application of lipidated peptides and proteins  

Microsoft Academic Search

We have developed a basic concept for studying cell biological phenomena using an interdisciplinary approach starting from organic chemistry. Based on structural information available for a given biological phenomenon, unsolved chemical problems are identified. For their solution, new synthetic pathways and methods are developed, which reflect the state of the art in synthesising lipidated peptide conjugates. These compounds are used

Carsten Peters; Melanie Wagner; Martin Völkert; Herbert Waldmann

2002-01-01

346

Tetraglyme Trap for the Determination of Volatile Organic Compounds in Urban Air: Projects for Undergraduate Analytical Chemistry  

ERIC Educational Resources Information Center

The differences in the levels of volatile organic compounds (VOCs), in the ambient air from the two urban locations, were studied by the undergraduate analytical chemistry students. Tetraglyme is very widely used due to its simplicity and its potential for use to investigate VOCs in ambient and indoor air employing a purge-and-trap concentrator…

Hope, Wilbert W.; Johnson, Clyde; Johnson, Leon P.

2004-01-01

347

COMPUTATIONAL CHEMISTRY METHOD FOR PREDICTING VAPOR PRESSURES AND ACTIVITY COEFFICIENTS OF POLAR ORGANIC OXYGENATES IN PM2.5  

EPA Science Inventory

Parameterizations of interactions of polar multifunctional organic oxygenates in PM2.5 must be included in aerosol chemistry models for evaluating control strategies for reducing ambient concentrations of PM2.5 compounds. Vapor pressures and activity coefficients of these compo...

348

New insights into prebiotic chemistry from Stanley Miller's spark discharge experiments.  

PubMed

1953 was a banner year for biological chemistry: The double helix structure of DNA was published by Watson and Crick, Sanger's group announced the first amino acid sequence of a protein (insulin) and the synthesis of key biomolecules using simulated primordial Earth conditions has demonstrated by Miller. Miller's studies in particular transformed the study of the origin of life into a respectable field of inquiry and established the basis of prebiotic chemistry, a field of research that investigates how the components of life as we know it can be formed in a variety of cosmogeochemical environments. In this review, I cover the continued advances in prebiotic syntheses that Miller's pioneering work has inspired. The main focus is on recent state-of-the-art analyses carried out on archived samples of Miller's original experiments, some of which had never before been analyzed, discovered in his laboratory material just before his death in May 2007. One experiment utilized a reducing gas mixture and an apparatus configuration (referred to here as the "volcanic" apparatus) that could represent a water-rich volcanic eruption accompanied by lightning. Another included H(2)S as a component of the reducing gas mixture. Compared to the limited number of amino acids Miller identified, these new analyses have found that over 40 different amino acids and amines were synthesized, demonstrating the potential robust formation of important biologic compounds under possible cosmogeochemical conditions. These experiments are suggested to simulate long-lived volcanic island arc systems, an environment that could have provided a stable environment for some of the processes thought to be involved in chemical evolution and the origin of life. Some of the alternatives to the Miller-based prebiotic synthesis and the "primordial soup" paradigm are evaluated in the context of their relevance under plausible planetary conditions. PMID:23340907

Bada, Jeffrey L

2013-03-01

349

Analytical chemistry of the persistent organic pollutants identified in the Stockholm Convention: A review.  

PubMed

Persistent organic pollutants (POPs) are major environmental concern due to their persistence, long-range transportability, bio-accumulation and potentially adverse effects on living organisms. Analytical chemistry plays an essential role in the measurement of POPs and provides important information on their distribution and environmental transformations. Much effort has been devoted during the last two decades to the development of faster, safer, more reliable and more sensitive analytical techniques for these pollutants. Since the Stockholm Convention (SC) on POPs was adopted 12 years ago, analytical methods have been extensively developed. This review article introduces recent analytical techniques and applications for the determination of POPs in environmental and biota samples, and summarizes the extraction, separation and instrumental analyses of the halogenated POPs. Also, this review covers important aspects for the analyses of SC POPs (e.g. lipid determination and quality assurance/quality control (QA/QC)), and finally discusses future trends for improving the POPs analyses and for potential new POPs. PMID:23870403

Xu, Weiguang; Wang, Xian; Cai, Zongwei

2013-08-01

350

Reaction Mechanisms for the Limited Reversibility of Li-O2 Chemistry in Organic Carbonate Electrolytes  

SciTech Connect

The Li-O2 chemistry in nonaqueous carbonate electrolytes and the underneath reason of its limited reversibility was exhaustively investigated. The discharge products collected from the air cathode in a Li-O2 battery at different depth of discharge (DOD) were systematically analyzed with X-ray diffraction. It is revealed that, independent of the discharge depth, lithium alkylcarbonate (either lithium propylenedicarbonate - LPDC, or lithium ethylenedicarbonate - LEDC, with other related derivatives) and lithium carbonate (Li2CO3) are always the main products, obviously originated from the electrolyte solvents propylene carbonate (PC) and ethylene carbonate (EC). These lithium alkylcarbonates are obviously generated from the single-electron reductive decomposition of the corresponding carbonate solvents initiated by the attack of superoxide radical anions. On the other hand, neither lithium peroxide (Li2O2) nor lithium oxide (Li2O) is detected. More significantly, from in situ gas chromatography/mass spectroscopy it is found that Li2CO3 and Li2O cannot be oxidized even when charged up to 4.6 V vs. Li/Li+, while LPDC, LEDC and Li2O2 are readily able to, with CO2 and CO released with the re-oxidation of LPDC and LEDC. It is therefore concluded that the quasi-reversibility of Li-O2 chemistry observed hitherto in an organic carbonate-based electrolyte is actually reliant on the formation of lithium alkylcarbonates through the reductive decomposition of carbonate solvents during discharge process and the subsequent oxidation of these same alkylcarbonates during charge process. It is the poor oxidizability of these alkylcarbonate species that constitutes the obstruction to an ideal rechargeable Li-O2 battery.

Xu, Wu; Xu, Kang; Viswanathan, Vilayanur V.; Towne, Silas A.; Hardy, John S.; Xiao, Jie; Nie, Zimin; Hu, Dehong; Wang, Deyu; Zhang, Jiguang

2011-11-15

351

Global carbon tetrachloride distributions obtained from the Atmospheric Chemistry Experiment (ACE)  

NASA Astrophysics Data System (ADS)

The first study of the global atmospheric distribution of carbon tetrachloride (CCl4), as a function of altitude and latitude, was performed using solar occultation measurements obtained by the Atmospheric Chemistry Experiment (ACE) mission using Fourier transform spectroscopy. A total of 8703 profile measurements were taken in the upper troposphere and lower stratosphere between February 2004 and August 2007. The zonal distribution of carbon tetrachloride displays a slight hemispheric asymmetry and decreasing concentration with increasing altitude at all latitudes. Maximum carbon tetrachloride concentrations are situated below 10 km in altitude with VMR (Volume Mixing Ratio) values of 100-130 ppt (parts per trillion). The highest concentrations are located about the Equator and at mid-latitudes, particularly for latitudes in heavily industrialised regions (20-45° N), with values declining towards the poles. Global distributions obtained from ACE were compared with predictions from three chemistry transport models showing good agreement in terms of the vertical gradient despite an overall offset. The ACE dataset gives unique global and temporal coverage of carbon tetrachloride and its transport through the atmosphere. An estimated lifetime for carbon tetrachloride of 34±5 years was determined through correlation with CFC-11.

Allen, N. D. C.; Bernath, P. F.; Boone, C. D.; Chipperfield, M. P.; Fu, D.; Manney, G. L.; Oram, D. E.; Toon, G. C.; Weisenstein, D. K.

2009-10-01

352

Global carbon tetrachloride distributions obtained from the Atmospheric Chemistry Experiment (ACE)  

NASA Astrophysics Data System (ADS)

The first study of the global atmospheric distribution of carbon tetrachloride (CCl4), as a function of altitude and latitude, was performed using solar occultation measurements obtained by the Atmospheric Chemistry Experiment (ACE) mission using Fourier transform spectroscopy. A total of 8703 profile measurements were used in the study taken between February 2004 and August 2007. The zonal distribution of carbon tetrachloride displays a slight hemispheric asymmetry and decreasing concentration with increasing altitude at all latitudes. Maximum carbon tetrachloride concentrations are situated below 10 km in altitude with VMR (Volume Mixing Ratio) values of 100-130 ppt (parts per trillion). The highest concentrations are located about the equator and at mid-latitudes, particularly for latitudes in heavily industrialised regions (20-45° N), with values declining towards the poles. Global distributions obtained from ACE were compared with predictions from three chemistry transport models. The ACE dataset gives unique global and temporal coverage of carbon tetrachloride and its transport through the atmosphere. An estimated lifetime for carbon tetrachloride of 34±5 years was determined through correlation with CFC-11.

Allen, N. D. C.; Bernath, P. F.; Boone, C. D.; Chipperfield, M. P.; Fu, D.; Manney, G. L.; Toon, G. C.; Weisenstein, D. K.

2009-06-01

353

The 2001 Phoenix Sunrise Experiment: Vertical Mixing and Chemistry During the Morning Transition in Phoenix  

SciTech Connect

A field experiment was carried out in Phoenix during June 2001 to examine the role of vertical mixing on the ozone chemistry of the boundary layer during the morning transition from stable to unstable atmospheric conditions. A combination of surface instruments, instruments located on two floors of a 39-story building in downtown Phoenix, and an instrumented airplane was used to characterize the evolving chemistry in the lowest 650 m of the atmosphere. Remote sensing and in situ platforms were used to obtained detailed profiles of winds and temperatures during the early morning hours and for several hours after sunrise. The analysis presented in this paper focuses on vertical profiles of CO, ozone, and NO/NOy measured on the building and their relationship to the morning boundary layer evolution over Phoenix. Some features were found that are consistent with a simple conceptual picture of nighttime trapping of pollutants in a stable surface layer and a subsequent release the following morning. In some instances, however, evidence of significant vertical mixing was found during the early morning well before the times expected for the development of convective mixing after sunrise. A satisfactory explanation for these observations has not yet been found.

Doran, J C.; Berkowitz, Carl M.; Coulter, Richard L.; Shaw, William J.; Spicer, Chet W.

2003-05-01

354

Improving Students' Understanding of Molecular Structure through Broad-Based Use of Computer Models in the Undergraduate Organic Chemistry Lecture  

ERIC Educational Resources Information Center

Several articles suggest how to incorporate computer models into the organic chemistry laboratory, but relatively few papers discuss how to incorporate these models broadly into the organic chemistry lecture. Previous research has suggested that "manipulating" physical or computer models enhances student understanding; this study…

Springer, Michael T.

2014-01-01

355

Normal and Inverse Ferrite Spinels: A Set of Solid State Chemistry Related Experiments.  

ERIC Educational Resources Information Center

Presents one of the themes of a French chemistry college laboratory course, which concerns the field of solid state chemistry and is focused on the study of the cation distribution in the case of certain spinel ferrites. (HM)

Chaumont, C.; Burgard, M.

1979-01-01

356

Research in physical chemistry and chemical education: Part A: Water Mediated Chemistry of Oxidized Atmospheric Compounds Part B: The Development of Surveying Tools to Determine How Effective Laboratory Experiments Contribute to Student Conceptual Understanding  

NASA Astrophysics Data System (ADS)

This dissertation is a combination of two research areas, experimental physical chemistry, Chapters I to V, and chemical education, Chapters VI to VII. Chapters I to V describe research on the water-mediated chemistry of oxidized atmospheric molecules and the impact that water has on the spectra of these environmental systems. The role of water in the Earth's atmosphere has been of considerable interest due to its ability to impact chemistry and climate. Oxidized atmospheric molecules in the presence of water have the ability to form hydrogen bonded water complexes. The spectroscopic investigation of nitric acid-water complexes, outlined in Chapter III, was undertaken to characterize intermolecular hydrogen bonds in a water-restricted environment at ambient temperatures. Additionally, this characterization of nitric acid-water complexes allowed for the comparison of calculated overtone OH-stretching vibrational band frequencies, intensities, and anharmonicities of intermolecular hydrogen-bonded water complexes with experimental observations. Oxidized organic molecules, such as aldehydes and ketones, in addition to forming hydrogen-bonded water complexes can undergo a hydration reaction of the carbonyl group and form germinal diols in the presence of water. This chemistry has been studied extensively in bulk aqueous media, however little is known about this process in the gas-phase at low water concentrations. The focus of the studies outlined in Chapters IV and V is motivated by the ability of pyruvic acid and formaldehyde to form germinal diols and water complexes in water-restricted environment. This water-mediated chemistry changes the physical and chemical properties of these organic molecules, therefore, impacting the partitioning between gas and particle phase, as well as the chemistry and photochemistry of oxidized organic molecules in the Earth's atmosphere. The results presented in this dissertation may help resolve the significant discrepancy between atmospherically measured oxidized organic molecules and predictions of atmospheric models at different relative humidities. The chemical education portion of this manuscript presented in Chapters VI and VII includes the development of a survey to determine how effective a laboratory experiment is in contributing to students' understanding of fundamental chemistry. The specific example used is an electrochemical cell. Our initial results showed that while most of our students could answer quantitative questions about the operation of the cell, their conceptual understanding of the microscopic processes that occur within the cell was inconsistent with the material presented in class. In particular, we noticed that while many students were able to correctly describe the events that take place at the surface of the anode and cathode, their understanding of the events that take place at the salt bridge was lacking. In this investigation, we were able to confirm the misconceptions reported in previous studies. Our results suggest that a relatively modest, incremental revision of the experiment reduces these misconceptions and helped the students to develop a molecular-scale picture of the processes that occur within an electrochemical cell.

Maron, Marta Katarzyna

357

The Molecular Modeling Workbook for Organic Chemistry (by Warren J. Hehre, Alan J. Shusterman, and Janet E. Nelson)  

NASA Astrophysics Data System (ADS)

Wavefunction, Inc.: Irvine, CA, 1998. 307 pp. ISBN 1-890661-06-6. 30.00. This workbook is the latest in a series of "lab manuals" designed to increase the presence of molecular modeling and computational chemistry in undergraduate courses. The authors have designed the workbook to differ from its predecessors in two ways: the target audience is introductory organic chemistry students, and a CD-ROM containing files of molecules and data replaces the need for expensive molecular modeling software. It also differs from its predecessors in that the exercises in it are not really molecular modeling experiments. Instead, students are introduced to the field by viewing the results of computational work stored on the CD-ROM. The workbook is divided into 21 chapters, each of which covers a topic encountered in introductory-level organic chemistry. The sequence of chapters follows the sequence of topics that instructors of introductory organic courses might employ, allowing the workbook to be used with most modern organic chemistry texts. The heart of the workbook, though, is the CD-ROM included with the book. It contains files of molecules and their accompanying computational results as well as Spartan View, a software package that allows these models to be visualized. Although it does not allow actual calculations to be performed, Spartan View permits the user to rotate molecules, intermediates, and transition states and retrieve "precalculated" values of bond and dihedral angles, bond lengths, energies, dipole moments, charge, and frequency of vibration. Spartan View also allows the user to search molecules and intermediates for electron-rich or electron-poor regions by showing electrostatic potential as well as HOMOs and LUMOs. Some files allow for animation of reactions or conformational changes. Note, however, that since the data are just stored on the CD-ROM, not all the data are available for all files. Although performing calculations is not an option, Spartan View can be used to display models and data obtained using Spartan or MacSpartan and stored on a disk. In this way, student exercises can be customized by the instructor or the instructor can prepare customized examples for use in lecture. Each chapter in the workbook contains a series of 3 to 17 exercises that use models and associated data contained on the accompanying CD-ROM. The exercises are not simply cookbook procedures in which the student is directed how to solve a problem. Instead, the authors provide background in a two-part tutorial and several essays that describe the information that can be obtained through molecular modeling, and then introduce a problem in organic chemistry that can be addressed using molecular modeling. The student is left to determine how best to obtain the requested data. For example, an exercise in the chapter Acids & Bases directs the student to determine the atomic charges and view the electrostatic potential map of the conjugate bases of three organic acids. The student is not, however, told which menu to pull or button to push. At the end of the exercise, the student is directed to compare the reactivity of the acids with the data collected from Spartan View. The exercises are relatively easy to complete after spending a few minutes with the tutorials, and many require students to compare the results of calculations with the reactivity of the molecules as discussed in the traditional lecture portion of the course. In this sense, the workbook provides a meaningful link between molecular modeling exercises outside of class and activities in the classroom. While some exercises involve comparing the energies of intermediates or transition states, others are more like videos of processes. Instructors will find many of these to be useful as visual aids in lecture. Mechanisms of Ring Inversion, for example, allows the instructor to show the stepwise ring flip of cyclohexane. Although some of the animations are very similar to those contained on CD-ROMs that sometimes accompany textbooks, the exercises in this

Crouch, R. David

1999-09-01

358

A Capstone Writing Experience in Polymer Chemistry: Writing a Proposal for an Instrument Purchase  

NASA Astrophysics Data System (ADS)

A capstone writing experience for upper-level polymer chemistry is described in which students write a proposal to the management of a hypothetical company recommending for or against the purchase of a particular make and model of polymer characterization instrumentation. This project involves background research into the appropriate instrumental method, the collection of quotes and product information from instrumentation vendors, and the development of capital and operating budgets. The students evaluate this information and make value judgments as to whether any purchase is justified and, if so, they suggest which make and model should be purchased. The term papers are to be written for a nonspecialist audience, which forces the students to write the paper in terms that are accessible to the scientifically literate lay person. This exercise has value in its own right, produces an excellent assessment tool, and greatly helps the students once they proceed to permanent employment where such writing skills are highly valued.

Hunter, Allen D.

1998-11-01

359

Micelle-Mediated Extraction of Heavy Metals from Environmental Samples: An Environmental Green Chemistry Laboratory Experiment  

NASA Astrophysics Data System (ADS)

A new laboratory experiment in which students extract and analyze several metallic contaminants from environmental samples is presented. The experimental procedure employs extraction of the target analytes by using an environmentally-benign preconcentrating technique prior to the identifications, which are carried out with a flame atomic absorption spectrometer. The extraction procedure employs complexation of the metallic species via a chelating agent, entrapment and solubilization via micelle formation, and isolation via phase separation when the solution temperature is raised. The overall process involves preparation of standard solutions and construction of a calibration curve, analysis of water samples, and evaluation of the matrix effect, through the analysis of several spiked samples. As a part of the evaluation protocol, a reference sample is also analyzed. Students become familiar with basic principles of analytical, environmental, and green chemistry through a "real world" application.

Giokas, Dimosthenis L.; Paleologos, Evangelos K.; Karayannis, Miltiades I.

2003-01-01

360

MIR station atmospheric chemistry investigations: numerical simulation of the future space experiments  

NASA Astrophysics Data System (ADS)

Regular, long-term, g1obalscale measurements of atmospheric minor gaseous and aerosol composition (MGAC) by means ofdifferent instruments (PHOENIX, OZONE-MIR, ISTOK-1, DOPI) are planned on board the SPECTR and PRIRODA modules of the Space Station MIR during 1995-1998. The main characteristics of these devices are given. The principal goals of the space experiments are: investigations of the spatial and temporal MGAC variations, comparisons of different space-borne atmospheric chemistry sensors and their intercalibration, validation of the space MGAC measurements using different ground-based station and aircraft data, and studies of the molecular absorption in the atmosphere aimed to enhance an accuracy of radiative transfer atmospheric models. Special attention is . devoted to radiative transfer model (line-mixing, line-shift, line-narrowing, Non-LTE effects). The numerical estimations of the errors of the MGAC vertical profile retrievals using different device data are carried out.

Timofeyev, Yuriy M.

1995-12-01

361

Two-dimensional atmospheric transport and chemistry model - Numerical experiments with a new advection algorithm  

NASA Technical Reports Server (NTRS)

Extensive testing of the advective scheme proposed by Prather (1986) has been carried out in support of the California Institute of Technology-Jet Propulsion Laboratory two-dimensional model of the middle atmosphere. The original scheme is generalized to include higher-order moments. In addition, it is shown how well the scheme works in the presence of chemistry as well as eddy diffusion. Six types of numerical experiments including simple clock motion and pure advection in two dimensions have been investigated in detail. By comparison with analytic solutions, it is shown that the new algorithm can faithfully preserve concentration profiles, has essentially no numerical diffusion, and is superior to a typical fourth-order finite difference scheme.

Shia, Run-Lie; Ha, Yuk Lung; Wen, Jun-Shan; Yung, Yuk L.

1990-01-01

362

Carbon cycling and phytoplankton responses within highly-replicated shipboard carbonate chemistry manipulation experiments conducted around Northwest European Shelf Seas  

NASA Astrophysics Data System (ADS)

The ongoing oceanic uptake of anthropogenic carbon dioxide (CO2) is significantly altering the carbonate chemistry of seawater, a phenomenon referred to as ocean acidification. Experimental manipulations have been increasingly used to gauge how continued ocean acidification will potentially impact marine ecosystems and their associated biogeochemical cycles in the future; however, results amongst studies, particularly when performed on natural communities, are highly variable, which in part likely reflects inconsistencies in experimental approach. To investigate the potential for identification of more generic responses and greater experimentally reproducibility, we devised and implemented a series of highly replicated (n = 8), short term (2-4 days) multi-level (? 4 conditions) carbonate chemistry/nutrient manipulation experiments on a range of natural microbial communities sampled in Northwest European shelf seas. Carbonate chemistry manipulations and resulting biological responses were found to be highly reproducible within individual experiments and to a lesser extent between geographically different experiments. Statistically robust reproducible physiological responses of phytoplankton to increasing pCO2, characterized by a suppression of net growth for small sized cells (< 10 ?m), were observed in the majority of the experiments, irrespective of nutrient status. Remaining between-experiment variability was potentially linked to initial community structure and/or other site-specific environmental factors. Analysis of carbon cycling within the experiments revealed the expected increased sensitivity of carbonate chemistry to biological processes at higher pCO2 and hence lower buffer capacity. The results thus emphasize how biological-chemical feedbacks may be altered in the future ocean.

Richier, S.; Achterberg, E. P.; Dumousseaud, C.; Poulton, A. J.; Suggett, D. J.; Tyrrell, T.; Zubkov, M. V.; Moore, C. M.

2014-03-01

363

Reactions at surfaces in the atmosphere: integration of experiments and theory as necessary (but not necessarily sufficient) for predicting the physical chemistry of aerosols.  

PubMed

While particles have significant deleterious impacts on human health, visibility and climate, quantitative understanding of their formation, composition and fates remains problematic. Indeed, in many cases, even qualitative understanding is lacking. One area of particular uncertainty is the nature of particle surfaces and how this determines interactions with gases in the atmosphere, including water, which is important for cloud formation and properties. The focus in this Perspective article is on some chemistry relevant to airborne particles and especially to reactions occurring on their surfaces. The intent is not to provide a comprehensive review, but rather to highlight a few selected examples of interface chemistry involving inorganic and organic species that may be important in the lower atmosphere. This includes sea salt chemistry, nitrate and nitrite ion photochemistry, organics on surfaces and heterogeneous reactions of oxides of nitrogen on proxies for airborne mineral dust and boundary layer surfaces. Emphasis is on the molecular level understanding that can only be gained by fully integrating experiment and theory to elucidate these complex systems. PMID:19727483

Finlayson-Pitts, Barbara J

2009-09-28

364

Measurement of Henry's Law Constants Using Internal Standards: A Quantitative GC Experiment for the Instrumental Analysis or Environmental Chemistry Laboratory  

ERIC Educational Resources Information Center

An internal standard method applicable to undergraduate instrumental analysis or environmental chemistry laboratory has been designed and tested to determine the Henry's law constants for a series of alkyl nitriles. In this method, a mixture of the analytes and an internal standard is prepared and used to make a standard solution (organic solvent)…

Ji, Chang; Boisvert, Susanne M.; Arida, Ann-Marie C.; Day, Shannon E.

2008-01-01

365

Introductory Chemistry: A Molar Relaxivity Experiment in the High School Classroom  

PubMed Central

Dotarem and Magnevist, two clinically available magnetic resonance imaging (MRI) contrast agents, were assessed in a high school science classroom with respect to which is the better contrast agent. Magnevist, the more efficacious contrast agent, has negative side effects because its gadolinium center can escape from its ligand. However, Dotarem, though a less efficacious contrast agent, is a safer drug choice. After the experiment, students are confronted with the FDA warning on Magnevist, which enabled a discussion of drug efficacy versus safety. We describe a laboratory experiment in which NMR spin lattice relaxation rate measurements are used to quantify the relaxivities of the active ingredients of Dotarem and Magnevist. The spin lattice relaxation rate gives the average amount of time it takes the excited nucleus to relax back to the original state. Students learn by constructing molar relaxivity curves based on inversion recovery data sets that Magnevist is more relaxive than Dotarem. This experiment is suitable for any analytical chemistry laboratory with access to NMR. PMID:23929983

Dawsey, Anna C.; Hathaway, Kathryn L.; Kim, Susie; Williams, Travis J.

2013-01-01

366

The first-year teaching assistant experience in a chemistry department  

NASA Astrophysics Data System (ADS)

The purpose of this qualitative study was to use an ethnomethodological perspective to investigate the experience of first-year teaching assistants as they make the transition from being a "new TAs" to "experienced TAs" in the Chemistry Department at Purdue University. Three areas were investigated. First, the impact of the graduate student orientation program on the first-year experience was examined and evaluated. Second, the socialization of the teaching assistants was investigated, including the development of social relationships with peers, how TAs learn the culture of the department, and how TAs learn the role of the TA within the department. Finally the professionalism of the teaching assistants was investigated. This area of the TA experience included their self-efficacy, their confidence, their thoughts about what constitutes a good TA, an examination of their perceived strengths and weaknesses, and a comparison of the TAs' ideas versus those of the faculty and staff. The TAs in this project encountered several difficulties or points of confusion during their first year, due in part to inadequate training or poor communication in the department or with the TAs.

Hume, Nicole Lynn Cable

367

Organic crystal growth experiment facility (13-IML-1)  

NASA Technical Reports Server (NTRS)

The interesting nature of metal-like organic compounds composed of charge transfer complexes has been recently realized. Crystals of these complexes can usually be grown by the solution crystallization method. It is difficult to grow such organic crystals on Earth, especially from the chemical reactions through diffusion controlled process in the solutions, because of gravitational disturbances, or sedimentation. The International Microgravity Lab. (IML-1) Organic Crystal Growth with G-Gitter Preventive Measure (OCGP) experiment is expected to grow a single crystal large enough to allow its intrinsic physical properties to be measured and its detailed crystal structure to be determined. This experiment also attempts to assess the experimental conditions including the microgravity environment for further study of the fundamental process of solution crystallization, nucleation, and growth from supersaturated phases including chemical reactions. Microgravity disturbances, G-jitter, may be an important environmental factor in the experimental method to assess. The vibration damping effects on organic crystal growth can be carefully studied.

Kanbayashi, Akio

1992-01-01

368

A new Geoengineering Model Intercomparison Project (GeoMIP) experiment designed for climate and chemistry models  

NASA Astrophysics Data System (ADS)

A new Geoengineering Model Intercomparison Project (GeoMIP) experiment "G4 specified stratospheric aerosols" (short name: G4SSA) is proposed to investigate the impact of stratospheric aerosol geoengineering on atmospheric composition, climate, and the environment. In contrast to the earlier G4 GeoMIP experiment, which requires an emission of sulphur dioxide (SO2) into the model, a prescribed aerosol forcing file is provided to the community, to be consistently applied to future model experiments between 2020 and 2100. This stratospheric aerosol distribution, with a total burden of about 2 Tg S has been derived using the ECHAM5-HAM microphysical model, based on a continuous annual tropical emission of 8 Tg SO2 year-1. A ramp-up of geoengineering in 2020 and a ramp-down in 2070 over a period of two years are included in the distribution, while a background aerosol burden should be used for the last 3 decades of the experiment. The performance of this experiment using climate and chemistry models in a multi-model comparison framework will allow us to better understand the significance of the impact of geoengineering and the abrupt termination after 50 years on climate and composition of the atmosphere in a changing environment. The zonal and monthly mean stratospheric aerosol input dataset is available at https://www2.acd.ucar.edu/gcm/geomip-g4-specified-stratospheric-aerosol-data-set.

Tilmes, S.; Mills, M. J.; Niemeier, U.; Schmidt, H.; Robock, A.; Kravitz, B.; Lamarque, J.-F.; Pitari, G.; English, J. M.

2014-08-01

369

Responsive hydrogels produced via organic sol-gel chemistry for cell culture applications.  

PubMed

In this study, we report the synthesis of novel environmentally responsive polyurea hydrogel networks prepared via organic sol-gel chemistry and demonstrate that the networks can stabilize pH while releasing glucose both in simple aqueous media and in mammalian cell culture settings. Hydrogel formulations have been developed based on the combination of an aliphatic triisocyanate with pH-insensitive amine functional polyether and pH-sensitive poly(ethyleneimine) segments in a minimally toxic solvent suitable for the sol-gel reaction. The polyether component of the polyurea network is sufficiently hydrophilic to give rise to some level of swelling independent of environmental pH, while the poly(ethyleneimine) component contains tertiary amine groups providing pH sensitivity to the network in the form of enhanced swelling and release under acidic conditions. The reaction of these materials to form a network is rapid and requires no catalyst. The resultant material exhibits the desired pH-responsive swelling behavior and demonstrates its ability to simultaneously neutralize lactic acid and release glucose in both cell-free culture media and mammalian cell culture, with no detectable evidence of cytotoxicity or changes in cell behavior, in the case of either SA-13 human hybridomas or mouse embryonic stem cells. Furthermore, pH is observed to have a clear effect on the rate at which glucose is released from the hydrogel network. Such characteristics promise to maintain a favorable cell culture environment in the absence of human intervention. PMID:22561670

Patil, Smruti; Chaudhury, Pulkit; Clarizia, Lisa; McDonald, Melisenda; Reynaud, Emmanuelle; Gaines, Peter; Schmidt, Daniel F

2012-08-01

370

A cognitive model of second-year organic chemistry students' conceptualizations of mental molecular rotation  

NASA Astrophysics Data System (ADS)

The goal of this research was to answer the question, "What is a plausible explanation (model) of the cognitive structure and processes that facilitate mental molecular rotation?". This work used phenomenographic methodology and techniques of interview and think-aloud protocol. Constructivism was the theoretical framework. At the outset of the research, I designed nine tasks to obtain participant articulations of conceptualizations of mental molecular rotations. Articulations from five second-year organic chemistry students attending a Midwestern research university became the research data. Analysis produced four emerging themes along two axes: visualization representation and modeling cognition. These two axes formed a mental space, which was modeled by structure and processes that facilitated mental molecular rotation. A theoretical cognitive model of mental molecular rotation was based on the work of two researchers: Robbie Case and Richard Lesh. Lesh's "mental model" is composed of cognitive elements and operations, which are distributed over heeded local and global cognitive sub-models whereas Case deals with unheeded central conceptual structures. The models and structures interact to produce new knowledge and facilitate the use of existing knowledge. Two predictions of the theory of mental molecular rotation were elaborated. Students without a set of operations in a central conceptual structure will not be able to mentally rotate molecules. This is true even if a set of components, other than "operation", is constructed. The artifacts of mental molecular rotation can be used to determine the state of construction of the central conceptual structure responsible for mental molecular rotation.

Briggs, Michael W.

371

Secondary organic aerosol production from diesel vehicle exhaust: impact of aftertreatment, fuel chemistry and driving cycle  

NASA Astrophysics Data System (ADS)

Environmental chamber ("smog chamber") experiments were conducted to investigate secondary organic aerosol (SOA) production from dilute emissions from two medium-duty diesel vehicles (MDDVs) and three heavy-duty diesel vehicles (HDDVs) under urban-like conditions. Some of the vehicles were equipped with emission control aftertreatment devices including diesel particulate filters (DPF), selective catalytic reduction (SCR) and diesel oxidation catalysts (DOC). Experiments were also performed with different fuels (100% biodiesel and low-, medium- or high-aromatic ultralow sulfur diesel) and driving cycles (Unified Cycle, Urban Dynamometer Driving Schedule, and creep+idle). During normal operation, vehicles with a catalyzed DPF emitted very little primary particulate matter (PM). Furthermore, photo-oxidation of dilute emissions from these vehicles produced essentially no SOA (below detection limit). However, significant primary PM emissions and SOA production were measured during active DPF regeneration experiments. Nevertheless, under reasonable assumptions about DPF regeneration frequency, the contribution of regeneration emissions to the total vehicle emissions is negligible, reducing PM trapping efficiency by less than 2%. Therefore, catalyzed DPFs appear to be very effective in reducing both primary and secondary fine particulate matter from diesel vehicles. For both MDDVs and HDDVs without aftertreatment substantial SOA formed in the smog chamber - with the emissions from some vehicles generating twice as much SOA as primary organic aerosol after three hours of oxidation at typical urban VOC : NOx ratios (3:1). Comprehensive organic gas speciation was performed on these emissions, but less than half of the measured SOA could be explained by traditional (speciated) SOA precursors. The remainder presumably originates from the large fraction (~30%) of the non-methane organic gas emissions that could not be speciated using traditional one-dimensional gas-chromatography. The unspeciated organics - likely comprising less volatile species, such as intermediate volatility organic compounds - appear to be important SOA precursors; we estimate that the effective SOA yield (defined as the ratio of SOA mass to reacted precursor mass) was 9 ± 6% if both speciated SOA precursors and unspeciated organics are included in the analysis. SOA production from creep+idle operation was 3-4 times larger than SOA production from the same vehicle operated over the Urban Dynamometer Driving Schedule (UDDS). Fuel properties had little or no effect on primary PM emissions or SOA formation.

Gordon, T. D.; Presto, A. A.; Nguyen, N. T.; Robertson, W. H.; Na, K.; Sahay, K. N.; Zhang, M.; Maddox, C.; Rieger, P.; Chattopadhyay, S.; Maldonado, H.; Maricq, M. M.; Robinson, A. L.

2013-09-01

372

Secondary organic aerosol production from diesel vehicle exhaust: impact of aftertreatment, fuel chemistry and driving cycle  

NASA Astrophysics Data System (ADS)

Environmental chamber ("smog chamber") experiments were conducted to investigate secondary organic aerosol (SOA) production from dilute emissions from two medium-duty diesel vehicles (MDDVs) and three heavy-duty diesel vehicles (HDDVs) under urban-like conditions. Some of the vehicles were equipped with emission control aftertreatment devices, including diesel particulate filters (DPFs), selective catalytic reduction (SCR) and diesel oxidation catalysts (DOCs). Experiments were also performed with different fuels (100% biodiesel and low-, medium- or high-aromatic ultralow sulfur diesel) and driving cycles (Unified Cycle,~Urban Dynamometer Driving Schedule, and creep + idle). During normal operation, vehicles with a catalyzed DPF emitted very little primary particulate matter (PM). Furthermore, photooxidation of dilute emissions from these vehicles produced essentially no SOA (below detection limit). However, significant primary PM emissions and SOA production were measured during active DPF regeneration experiments. Nevertheless, under reasonable assumptions about DPF regeneration frequency, the contribution of regeneration emissions to the total vehicle emissions is negligible, reducing PM trapping efficiency by less than 2%. Therefore, catalyzed DPFs appear to be very effective in reducing both primary PM emissions and SOA production from diesel vehicles. For both MDDVs and HDDVs without aftertreatment substantial SOA formed in the smog chamber - with the emissions from some vehicles generating twice as much SOA as primary organic aerosol after 3 h of oxidation at typical urban VOC / NOx ratios (3 : 1). Comprehensive organic gas speciation was performed on these emissions, but less than half of the measured SOA could be explained by traditional (speciated) SOA precursors. The remainder presumably originates from the large fraction (~30%) of the nonmethane organic gas emissions that could not be speciated using traditional one-dimensional gas chromatography. The unspeciated organics - likely comprising less volatile species such as intermediate volatility organic compounds - appear to be important SOA precursors; we estimate that the effective SOA yield (defined as the ratio of SOA mass to reacted precursor mass) was 9 ± 6% if both speciated SOA precursors and unspeciated organics are included in the analysis. SOA production from creep + idle operation was 3-4 times larger than SOA production from the same vehicle operated over the Urban Dynamometer Driving Schedule (UDDS). Fuel properties had little or no effect on primary PM emissions or SOA formation.

Gordon, T. D.; Presto, A. A.; Nguyen, N. T.; Robertson, W. H.; Na, K.; Sahay, K. N.; Zhang, M.; Maddox, C.; Rieger, P.; Chattopadhyay, S.; Maldonado, H.; Maricq, M. M.; Robinson, A. L.

2014-05-01

373

Simple coupling chemistry linking carboxyl-containing organic molecules to silicon oxide surfaces under acidic conditions.  

PubMed

The coupling chemistry of carboxymethylated amylose with organo-silanized silicon oxide surfaces at pH 7.4 and 2.0 was investigated using atomic force microscopy (AFM) based single-molecule force spectroscopy. At close to neutral pH, carbodiimide activation of a carboxylic acid affords formation of an amide bond with an amino surface linker. At pH 2.0, no activation with carbodiimide was required to anchor carboxymethylated amylose between an AFM tip and a glass substrate. At the same time, the mean bond rupture force f(r) dropped from 1.65 ± 0.37 nN at pH 7.4 to 1.39 ± 0.30 nN at pH 2.0 without carbodiimide, indicating that a different link to the surface can be formed at low pH. The coupling mechanism at pH 2.0 was elucidated by a series of experiments, in which the surface was functionalized with four different organosilanes, each containing characteristic functional groups. The results are rationalized with an acid-catalyzed ester condensation between a carboxyl group and a free, unreacted silanol group in the surface anchor or on the surface. PMID:20822126

Schmidt, Sebastian W; Christ, Timo; Glockner, Christian; Beyer, Martin K; Clausen-Schaumann, Hauke

2010-10-01

374

The Titan Haze Simulation experiment on COSmIC: Probing Titan’s atmospheric chemistry at low temperature  

NASA Astrophysics Data System (ADS)

The aim of the Titan Haze Simulation (THS) experiment is to contribute to a better understanding of aerosol formation in Titan’s atmosphere through the study of the chemical formation pathways that link the simpler gas phase molecules resulting from the first steps of the N2-CH4 chemistry, to the more complex gas phase precursors of aerosols; and more specifically, to investigate the role of polycyclic aromatic hydrocarbons (PAHs) and nitrogenated polycyclic aromatic hydrocarbons (PANHs), among other hydrocarbons, in this process. In the THS experiment developed at the NASA Ames Cosmic simulation facility (COSmIC), Titan’s atmospheric chemistry is simulated by a pulsed plasma jet expansion at temperature conditions (?150 K) close to those found in Titan’s atmosphere in regions where aerosols are formed. In addition, because of the very short residence time of the gas in the plasma discharge, only the initial steps of the chemistry occur, making the COSmIC/THS a unique tool to study the first and intermediate (when adding heavier precursors to the initial N2-CH4 mixture) steps of Titan’s atmospheric chemistry at low temperature as shown in the study presented here. We further illustrate the potential of COSmIC/THS for the simulation of Titan’s atmospheric chemistry by presenting very promising results from a preliminary comparison of the laboratory data to data from the Cassini Plasma Spectrometer-Ion Beam Spectrometer (CAPS-IBS) instrument.

Sciamma-O'Brien, Ella; Ricketts, Claire L.; Salama, Farid

2014-11-01

375

An Advanced Analytical Chemistry Experiment Using Gas Chromatography-Mass Spectrometry, MATLAB, and Chemometrics to Predict Biodiesel Blend Percent Composition  

ERIC Educational Resources Information Center

We present a laboratory experiment for an advanced analytical chemistry course where we first focus on the chemometric technique partial least-squares (PLS) analysis applied to one-dimensional (1D) total-ion-current gas chromatography-mass spectrometry (GC-TIC) separations of biodiesel blends. Then, we focus on n-way PLS (n-PLS) applied to…

Pierce, Karisa M.; Schale, Stephen P.; Le, Trang M.; Larson, Joel C.

2011-01-01

376

The Quantitative Resolution of a Mixture of Group II Metal Ions by Thermometric Titration with EDTA. An Analytical Chemistry Experiment.  

ERIC Educational Resources Information Center

Presents an experiment in thermometric titration used in an analytic chemistry-chemical instrumentation course, consisting of two titrations, one a mixture of calcium and magnesium, the other of calcium, magnesium, and barium ions. Provides equipment and solutions list/specifications, graphs, and discussion of results. (JM)

Smith, Robert L.; Popham, Ronald E.

1983-01-01

377

Utilization of a Microcomputer for the Study of an Iodine Oxidation and Equilibrium Reaction: A Physical Chemistry Experiment.  

ERIC Educational Resources Information Center

Describes a physical chemistry experiment which incorporates the use of a microcomputer to enhance understanding of combined kinetic and equilibrium phenomena, to increase experimental capabilities when working with large numbers of students and limited equipment, and for the student to develop a better understanding of experimental design. (JN)

Julien, L. M.

1984-01-01

378

Binary Solid-Liquid Phase Diagram of Phenol and t-Butanol: An Undergraduate Physical Chemistry Experiment  

ERIC Educational Resources Information Center

The determination of the solid-liquid phase diagram of a binary system is always used as an experiment in the undergraduate physical chemistry laboratory courses. However, most phase diagrams investigated in the lab are simple eutectic ones, despite the fact that complex binary solid-liquid phase diagrams are more common. In this article, the…

Xu, Xinhua; Wang, Xiaogang; Wu, Meifen

2014-01-01

379

Temperature and Electron Density Determination on Laser-Induced Breakdown Spectroscopy (LIBS) Plasmas: A Physical Chemistry Experiment  

ERIC Educational Resources Information Center

This laboratory is designed for physical chemistry students to gain experience using laser-induced breakdown spectroscopy (LIBS) in understanding plasma diagnostics. LIBS uses a high-powered laser that is focused on the sample causing a plasma to form. The emission of this plasma is then spectrally resolved and detected. Temperature and electron…

Najarian, Maya L.; Chinni, Rosemarie C.

2013-01-01

380

Preparation and Reactions of the 1,1-Dithiolato Complexes of Ni(II). An Undergraduate Coordination Chemistry Experiment.  

ERIC Educational Resources Information Center

Described is an undergraduate coordination chemistry experiment that enables students to relate concepts developed in class about the stereochemistry and coordination numbers to the interpretation of the electronic and infrared spectra and their magnetic behavior. Indicates that thermal decomposition and x-ray diffraction studies can also be…

Ballester, L.; Perpinan, M. F.

1988-01-01

381

Ionic Strength Effect on the Rate of Reduction of Hexacyanoferrate (III) by Ascorbic Acid: A Physical Chemistry Laboratory Experiment.  

ERIC Educational Resources Information Center

Describes a physical chemistry experiment that allows students to test the effect of ionic strength on the rates of a reaction between ions. The reduction of hexacyanoferrate III by ascorbic acid is detailed. Comparisons with the iodine clock reaction are made. (CS)

Watkins, Kenneth W.; Olson, June A.

1980-01-01

382

The ORGANIC Experiment on the ISS EXPOSE-R  

NASA Astrophysics Data System (ADS)

Polycyclic aromatic hydrocarbons (PAHs) and aromatic networks are among the most abundant organic material in space. PAHs and fullerenes have been identified in meteorites and are proposed as carriers for numerous astronomical absorption and emission features. Recently the fullerenes C60 and C70 have been discovered in a young planetary nebula, Tc 1 and in other astronomical environments. Thin films of selected PAHs and fullerenes have been subjected to the low Earth orbit environment as part of the ORGANIC experiment on the multi-user facility EXPOSE-R, which was deployed onboard the International Space Station (ISS) in March 2009 and retrieved by extra-vehicular activity (EVA) in January 2011. The ORGANIC experiment monitors the chemical evolution, survival, destruction, and chemical modification of PAHs and fullerenes exposed to solar illumination and cosmic radiation. The radiation dose that is collected on the ISS by the samples cannot be accurately simulated in Earth laboratories. Dark samples are shielded from the UV photons and will enable us to differentiate between the effects of exposure to photons and cosmic rays. The samples are monitored before and after space exposure; ground control samples were continuously monitored. We describe the ORGANIC experiment on the Space Station and report on laboratory ground-control measurements in the UV-Vis-NIR at NASA-Ames. Extended space exposure allows us to collect data on multiple samples which can be extrapolated to other astrophysical environments and thus greatly enhance our knowledge on the evolution of organic compounds in space environment.

Bryson, K.; Peeters, Z.; Salama, F.; Foing, B.; Ehrenfreund, P.; Jessberger, E.; Bischoff, A.; Breitfellner, M.; Schmidt, W.

2011-05-01

383

Chemistry of carbon nanomaterials: Uses of lithium nanotube salts in organic syntheses and functionalization of graphite  

NASA Astrophysics Data System (ADS)

The effective utilization of carbon nanomaterials, such as single-walled carbon nanotubes (SWNTs) and graphite, has been hindered due to difficulties (poor solubility, poly-dispersity) in processing. Therefore, a high degree of sidewall functionalization, either covalent or non-covalent, is often required to overcome these difficulties as the functionalized nanomaterials exhibit better solubility (either in organic solvents or in water), dispersity, manipulation, and processibility. This thesis presents a series of convenient and efficient organic synthetic routes to functionalize carbon nanomaterials. Carbon nanotube salts, prepared by treating SWNTs with lithium in liquid ammonia, react readily with aryl halides to yield aryl-functionalized SWNTs. These arylated SWNTs are soluble in methanol and water upon treatment with oleum. Similarly, SWNTs can be covalently functionalized by different heteroatoms (nitrogen, oxygen, and sulfur). Using the reductive alkylation approach, a synthetic scheme is designed to prepare long chain carboxylic acid functionalized SWNTs [SWNTs-(RCOOH)] that can react with (1) amine-terminated polyethylene glycol (PEG) chains to yield water-soluble biocompatible PEGylated SWNTs that are likely to be useful in a variety of biomedical applications; (2) polyethyleneimine (PEI) to prepare a SWNTs-PEI based adsorbent material that shows a four-fold improvement in the adsorption capacity of carbon dioxide over commonly used materials, making it useful for regenerable carbon dioxide removal in spaceflight; (3) chemically modified SWNTs-(RCOOH) to permit covalent bonding to the nylon matrix, thus allowing the formation of nylon 6,10 and nylon 6,10/SWNTs-(RCOOH) nanocomposites. Furthermore, we find that the lithium salts of carbon nanotubes serve as a source of electrons to induce polymerization of simple alkenes and alkynes onto the surface of carbon nanotubes. In the presence of sulfide/disulfide bonds, SWNT salts can initiate the single electron transfer (SET) mechanism to functionalize carbon nanotubes with different alkyl/aryl groups. Using the reductive alkylation approach, we can also functionalize graphites by alkyl/carboxylic acid groups, making graphite soluble in organic solvents and water. Tailoring of graphite layers is also accomplished by using different metals in liquid ammonia. Finally, SWNT-epoxides/graphite epoxides are synthesized using m-CPBA. Quantification of the epoxide substituents on the nanotube/graphite surface is evaluated through the catalytic de-epoxidation reaction using MeReO 3/PPh3 as heterogeneous catalyst. In summary, the proposed covalent functionalization methods yield derivatized nanomaterials that can provide a solid platform for a number of exciting applications, ranging from material science to biomedical devices. Furthermore, the results presented in this thesis provide insight into the molecular chemistry at nano-resolution.

Chattopadhyay, Jayanta

384

Teaching a Modified Hendrickson, Cram, and Hammond Curriculum in Organic Chemistry. Curriculum Redesign To Turn Around Student Performance  

NASA Astrophysics Data System (ADS)

Prior to the 2004 2005 academic year, a variety of indicators suggested a severe problem with the two-semester organic chemistry series at Elon University, a private, liberal arts institution with an enrollment averaging about 4500 undergraduate students. Student evaluations of teaching for organic chemistry were below the university average, the student attrition rate was near 50%, students exhibited poor competency with mechanisms, and scores on the ACS final exam were quite low. In the fall of 2004, we introduced a new curriculum, reminiscent of the approach by Hendrickson, Cram, and Hammond. In this new curriculum, fundamental concepts are introduced before mechanisms, and mechanisms are introduced before reactions. Reactions are introduced according to similarities among mechanisms rather than the functional group involved. After the implementation of that curriculum, substantially positive changes were observed for all of the above indicators. This report examines which factors may be the specific causes of these positive changes.

Karty, Joel M.; Gooch, Gene; Gray Bowman, B.

2007-07-01

385

The Binding Constant for Complexation of Bilirubin to Bovine Serum Albumin. An Experiment for the Biophysical Chemistry Laboratory  

NASA Astrophysics Data System (ADS)

Students use fluorescence spectroscopy to measure the binding constant for bilirubin-bovine serum albumin complexation by the Method of Continuous Variations. The experiment applies fundamental concepts of physical chemistry to a commercially available system of biological interest. The experiment is easily completed in a single laboratory period, and students obtain binding constants on the order of 10 7, in good agreement with literature values.

Williams, Kathryn R.; Adhyaru, Bhavin; Pierce, Russell E.; Schulman, Stephen G.

2002-01-01

386

An overview of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx)  

NASA Astrophysics Data System (ADS)

The Chemistry-Aerosol Mediterranean Experiment (ChArMEx, http://charmex.lsce.ipsl.fr) is a French initiative of the MISTRALS meta-programme (Mediterranean Integrated Studies at Regional And Locals Scales, http://www.mistrals-home.org). It federates a great number of national and international cooperative research actions aiming at a scientific assessment of the present and future state of the atmospheric environment in the Mediterranean Basin, and of its impacts on the regional climate, air quality, and marine biogeochemistry. The target is short-lived particulate and gaseous tropospheric trace species which are the cause of poor air quality events, have two-way interactions with climate, or impact the marine biogeochemistry, in a context of strong regional anthropogenic and climatic pressures. The six ChArMEx work packages include Emissions, Chemical processes and ageing, Transport processes and air quality, Aerosol-radiation-climate interactions, Deposition, and Present and future variability and trends. For several years, efforts have been deployed in several countries to develop (i) a network of relevant stations for atmospheric chemistry at background sites on islands and continental coasts around the basin and (ii) several intensive field campaigns including the operation of surface supersites and various instrumented mobile platforms (large and ultra-light aircraft, sounding and drifting balloons, ZeroCO2 sailboat). This presentation is an attempt to provide an overview of the various experimental, remote sensing and modelling efforts produced and to highlight major findings, by referencing more detailed ChArMEx presentations given in this conference and recently published or submitted papers. During the first phase of the project experimental efforts have been mainly concentrated on the western basin. Plans for the 2nd phase of ChArMEx, more dedicated towards the eastern basin, will also be given. In particular we plan to develop monitoring activities at Cyprus and put more emphasis (i) on aerosol-cloud interactions in cooperation with the FP7/Environment project BACCHUS, (ii) the budget and transport of anthropogenic emissions from megacities, and (iii) processes at the air-sea interface with a proposal for a 1-month oceanographic cruise during a period of dust deposition events, joint with the biogeochemistry component of MISTRALS (project MERMEX: the Marine Ecosystem Response Mediterranean Experiment). Acknowledgements: ChArMEx activities involve about 50 institutes. FD expresses his gratitude to every contributing scientist. ChArMEx is supported by too many agencies for listing them all here. The main overall effort is from France, with ADEME, ANR, CNES, CNRS-INSU, the Collectivité Territoriale de Corse (incl. EU-FEDER funds), Météo-France, CEA and Ecole des Mines de Douai as the main funding agencies.

Dulac, François

2014-05-01

387

Research Paper Meteor Wake in High Frame-Rate Images— Implications for the Chemistry of Ablated Organic Compounds  

Microsoft Academic Search

Extraterrestrial organic matter may have been chemically altered into forms more ameanable for prebiotic chemistry in the wake of a meteor after ablation. We measured the rate of cool- ing of the plasma in the meteor wake from the intensity decay just behind a meteoroid by freezing its motion in high frame-rate 1,000 frames\\/s video images, with an intensified cam-

PETER JENNISKENS; HANS C. STENBAEK-NIELSEN

388

Mercury Redox Chemistry in the Negro River Basin, Amazon: The Role of Organic Matter and Solar Light  

Microsoft Academic Search

Pristine water bodies in the Negro River basin, Brazilian Amazon, show relatively high concentrations of mercury. These waters\\u000a are characterized by acidic pH, low concentrations of suspended solids, and high amounts of dissolved organic matter and are\\u000a exposed to intense solar radiation throughout the year. This unique environment creates a very dynamic redox chemistry affecting\\u000a the mobility of mercury due

Wilson F. JardimMarcia; Márcia Cristina Bisinoti; Pedro Sérgio Fadini; Gilmar Silvério da Silva

2010-01-01

389

The effects of instructors' autonomy support and students' autonomous motivation on learning organic chemistry: A self-determination theory perspective  

Microsoft Academic Search

This prospective study applied self-determination theory to investigate the effects of students' course-specific self-regulation and their perceptions of their instructors' autonomy support on adjustment and academic performance in a college-level organic chemistry course. The study revealed that: (1) students' reports of entering the course for relatively autonomous (vs. controlled) reasons predicted higher perceived competence and interest\\/enjoyment and lower anxiety and

Aaron E. Black; Edward L. Deci

2000-01-01

390

Aerobic Alcohol Oxidation Using a Copper(I)/TEMPO Catalyst System: A Green, Catalytic Oxidation Reaction for the Undergraduate Organic Chemistry Laboratory  

ERIC Educational Resources Information Center

Modern undergraduate organic chemistry textbooks provide detailed discussion of stoichiometric Cr- and Mn-based reagents for the oxidation of alcohols, yet the use of such oxidants in instructional and research laboratories, as well as industrial chemistry, is increasingly avoided. This work describes a laboratory exercise that uses ambient air as…

Hill, Nicholas J.; Hoover, Jessica M.; Stahl, Shannon S.

2013-01-01

391

Eliciting Metacognitive Experiences and Reflection in a Year 11 Chemistry Classroom: An Activity Theory Perspective  

ERIC Educational Resources Information Center

Concerns regarding students' learning and reasoning in chemistry classrooms are well documented. Students' reasoning in chemistry should be characterized by conscious consideration of chemical phenomenon from laboratory work at macroscopic, molecular/sub-micro and symbolic levels. Further, students should develop metacognition in relation to such…

Thomas, Gregory P.; McRobbie, Campbell J.

2013-01-01

392

Cognitive ability experiment with photosensitive organic molecular thin films.  

PubMed

We present an optical experiment which permits us to evaluate the information exchange necessary to self-induce cooperatively a well-organized pattern in a randomly activated molecular assembly. A low-power coherent beam carrying polarization and wavelength information is used to organize a surface relief grating on a photochromic polymer thin film which is photoactivated by a powerful incoherent beam. We demonstrate experimentally that less than 1% of the molecules possessing information cooperatively transmit it to the entire photoactivated polymer film. PMID:16907620

Barille, Régis; Ahmadi-Kandjani, Sohrab; Ortyl, Ewelina; Kucharski, Stanislaw; Nunzi, Jean-Michel

2006-07-28

393

Experiments in Physical Chemistry, Sixth Edition (by David P. Shoemaker, Carl W. Garland, and Joseph W. Nibler)  

NASA Astrophysics Data System (ADS)

McGraw-Hill: New York, 1996. xii + 778 pp. ISBN 0-07-057074-4. Experiments in Physical Chemistry has long been one of the best textbooks available for undergraduate courses in physical chemistry laboratory. The present edition follows a similar format as previous editions, consisting of (i) a series of introductory sections dealing with common aspects of all experiments, such as recording of data, report writing, data and error analysis, and the use of computer software to aide in these, (ii) 48 experiments spanning 12 fundamental areas, and (iii) a series of resource chapters providing an introduction to electronics, instruments, techniques, and procedures commonly utilized in the performance of experiments in physical chemistry. Some needed changes have been incorporated in this edition, most notably the addition of sections that recognize the increased role of computers in modern experimentation. In particular, the section on computer software has been expanded and moved ahead of the experiments. The use of word processing, spreadsheets, and symbolic mathematics programs is emphasized, with examples using some of the most popular commercial programs. Three new experiments have been added and a fourth substantially modified. Each of the 44 other experiments has undergone some review and modernization, and a much-needed section on safety issues has been added to each. A resource chapter on computer interfacing, treating data types, programming languages and interfacing has been added. Examples are given for programming RS-232 communication and analog/digital interface boards using visual basic routines. I recommend this book be given serious consideration as a text for a one- or two-semester course in physical chemistry laboratory. The approach to experimentation in physical chemistry, the experiments, and the techniques that are described can form a solid basis for such a course. My one criticism is that the text offers only a limited number of laser-based experiments. This represents a minor drawback to an overall strong text, since those who wish to emphasize the use of lasers can easily supplement the choice of experiments from the numerous alternatives available in the literature.

Feigerle, Charles S.

1997-05-01

394

Filtrates & Residues. Acid Pickling with Amines: An Experiment in Applied Chemistry for High School or Freshman Chemistry.  

ERIC Educational Resources Information Center

This article gives a brief description of the process of the removal of corrosion and millscale from the surfaces of ferrous metals by acid pickling. It suggests an experiment to illustrate this process including the procedure and a discussion of the results. (CW)

Spears, Steven G.; And Others

1988-01-01

395

Phytoplankton responses and associated carbon cycling during shipboard carbonate chemistry manipulation experiments conducted around Northwest European shelf seas  

NASA Astrophysics Data System (ADS)

The ongoing oceanic uptake of anthropogenic carbon dioxide (CO2) is significantly altering the carbonate chemistry of seawater, a phenomenon referred to as ocean acidification. Experimental manipulations have been increasingly used to gauge how continued ocean acidification will potentially impact marine ecosystems and their associated biogeochemical cycles in the future; however, results amongst studies, particularly when performed on natural communities, are highly variable, which may reflect community/environment-specific responses or inconsistencies in experimental approach. To investigate the potential for identification of more generic responses and greater experimentally reproducibility, we devised and implemented a series (n = 8) of short-term (2-4 days) multi-level (?4 conditions) carbonate chemistry/nutrient manipulation experiments on a range of natural microbial communities sampled in Northwest European shelf seas. Carbonate chemistry manipulations and resulting biological responses were found to be highly reproducible within individual experiments and to a lesser extent between geographically separated experiments. Statistically robust reproducible physiological responses of phytoplankton to increasing pCO2, characterised by a suppression of net growth for small-sized cells (<10 ?m), were observed in the majority of the experiments, irrespective of natural or manipulated nutrient status. Remaining between-experiment variability was potentially linked to initial community structure and/or other site-specific environmental factors. Analysis of carbon cycling within the experiments revealed the expected increased sensitivity of carbonate chemistry to biological processes at higher pCO2 and hence lower buffer capacity. The results thus emphasise how biogeochemical feedbacks may be altered in the future ocean.

Richier, S.; Achterberg, E. P.; Dumousseaud, C.; Poulton, A. J.; Suggett, D. J.; Tyrrell, T.; Zubkov, M. V.; Moore, C. M.

2014-09-01

396

"OrganicPad": An Interactive Freehand Drawing Application for Drawing Lewis Structures and the Development of Skills in Organic Chemistry  

ERIC Educational Resources Information Center

Lewis structures are important for learning chemistry as they serve as an essential link between the structure of chemical compounds and their function. Unfortunately, the creation of valid Lewis structures remains an elusive goal for many students. In recent years, several web-based programs have been created that allow students to receive…

Cooper, Melanie M.; Grove, Nathaniel P.; Pargas, Roy; Bryfczynski, Sam P.; Gatlin, Todd

2009-01-01

397

Modelling non-equilibrium secondary organic aerosol formation and evaporation with the aerosol dynamics, gas- and particle-phase chemistry kinetic multi-layer model ADCHAM  

NASA Astrophysics Data System (ADS)

We have developed the novel Aerosol Dynamics, gas- and particle-phase chemistry model for laboratory CHAMber studies (ADCHAM). The model combines the detailed gas phase Master Chemical Mechanism version 3.2, an aerosol dynamics and particle phase chemistry module (which considers acid catalysed oligomerization, heterogeneous oxidation reactions in the particle phase and non-ideal interactions between organic compounds, water and inorganic ions) and a kinetic multilayer module for diffusion limited transport of compounds between the gas phase, particle surface and particle bulk phase. In this article we describe and use ADCHAM to study: (1) the mass transfer limited uptake of ammonia (NH3) and formation of organic salts between ammonium (NH4+) and carboxylic acids (RCOOH), (2) the slow and almost particle size independent evaporation of ?-pinene secondary organic aerosol (SOA) particles, and (3) the influence of chamber wall effects on the observed SOA formation in smog chambers. ADCHAM is able to capture the observed ?-pinene SOA mass increase in the presence of NH3(g). Organic salts of ammonium and carboxylic acids predominantly form during the early stage of SOA formation. These salts contribute substantially to the initial growth of the homogeneously nucleated particles. The model simulations of evaporating ?-pinene SOA particles support the recent experimental findings that these particles have a semi-solid tar like amorphous phase state. ADCHAM is able to reproduce the main features of the observed slow evaporation rates if low-volatility and viscous oligomerized SOA material accumulates in the particle surface layer upon evaporation. The evaporation rate is mainly governed by the reversible decomposition of oligomers back to monomers. Finally, we demonstrate that the mass transfer limited uptake of condensable organic compounds onto wall deposited particles or directly onto the Teflon chamber walls of smog chambers can have profound influence on the observed SOA formation. During the early stage of the SOA formation the wall deposited particles and walls themselves serve as a SOA sink from the air to the walls. However, at the end of smog chamber experiments the semi-volatile SOA material may start to evaporate from the chamber walls. With these three model applications, we demonstrate that several poorly quantified processes, i.e. mass transport limitations within the particle phase, oligomerization, heterogeneous oxidation, organic salt formation, and chamber wall effects can have substantial influence on the SOA formation, lifetime, chemical and physical particle properties, and their evolution. In order to constrain the uncertainties related to these processes, future experiments are needed where as many of the influential variables as possible are varied. ADCHAM can be a valuable model tool in the design and analysis of such experiments.

Roldin, P.; Eriksson, A. C.; Nordin, E. Z.; Hermansson, E.; Mogensen, D.; Rusanen, A.; Boy, M.; Swietlicki, E.; Svenningsson, B.; Zelenyuk, A.; Pagels, J.

2014-01-01

398

Environmental chemistry. Seventh edition  

SciTech Connect

This book presents a basic understanding of environmental chemistry and its applications. In addition to providing updated materials in this field, the book emphasizes the major concepts essential to the practice of environmental chemistry. Topics of discussion include the following: toxicological chemistry; toxicological chemistry of chemical substances; chemical analysis of water and wastewater; chemical analysis of wastes and solids; air and gas analysis; chemical analysis of biological materials and xenobiotics; fundamentals of chemistry; and fundamentals of organic chemistry.

Manahan, S.E. [Univ. of Missouri, Columbia, MO (United States)

1999-11-01

399

A Green Starting Material for Electrophilic Aromatic Substitution for the Undergraduate Organic Laboratory  

ERIC Educational Resources Information Center

Electrophilic aromatic substitution (EAS) experiment is designed for the second-semester and undergraduate organic chemistry laboratory. In the EAS experiment, the principles of green chemistry are discussed and illustrated in conjunction with the presentation of electrophilic aromatic substitution.

Jones-Wilson, T. Michelle; Burtch, Elizabeth A.

2005-01-01

400

Kinetics and Thermodynamics of Au Colloid Monolayer Self-Assembly: Undergraduate Experiments in Surface and Nanomaterials Chemistry  

NASA Astrophysics Data System (ADS)

This paper describes three closely related experiments utilizing colloidal Au nanoparticles to teach basic concepts in physical chemistry. This is done in the context of surface chemistry and nanomaterials synthesis, areas of intense current research interest in both academics and industry. First, students investigate the optical properties and stability of aqueous Au colloidal suspensions, determining the amount of a protein (protein A) necessary to prevent salt-induced flocculation of colloidal Au. Then, the kinetics of Au nanoparticle surface immobilization on silanized glass slides is followed by visible spectrophotometry. Data are fit to a (time)1/2 curve that describes particle diffusion and adsorption from an unstirred solution onto a planar substrate. Finally, the adsorption isotherm data are fit to a Frumkin isotherm, demonstrating the effects of interparticle repulsions upon the thermodynamics of Au particle monolayer formation. Each experiment benefits from the intense visible absorption of colloidal Au particles, allowing all aspects of surface assembly to be monitored using only a spectrophotometer.

Keating, Christine D.; Musick, Michael D.; Keefe, Melinda H.; Natan, Michael J.

1999-07-01

401

Projectile compositions and modal frequencies on the chemistry of micrometeoroids LDEF experiment  

NASA Technical Reports Server (NTRS)

The Chemistry of Micrometeoroids Experiment (LDEF instrument A0187-1) exposed witness plates of high-purity gold (greater than 99.99 percent Au) and commercial aluminum (greater than 99 percent Al) with the objective of analyzing the residues of cosmic-dust and orbital-debris particles associated with hypervelocity impact craters. The gold substrates were located approximately 8 deg off LDEF's trailing edge (Bay A03), while the aluminum surfaces resided in Bay A11, approximately 52 deg from LDEF's leading edge. SEM-EDX techniques were employed to analyze the residues associated with 199 impacts on the gold and 415 impacts on the aluminum surfaces. The residues that could be analyzed represent natural or man-made materials. The natural particles dominate at all particle sizes less than 5 micron. It is possible to subdivide both particle populations into subclasses. Chondritic compositions dominate the natural impactors (71 percent), followed by monomineralic, mafic-silicate compositions (26 percent), and by Fe-Ni rich sulfides (approximately 3 percent). Approximately 30 percent of all craters on the gold collectors were caused by man-made debris such as aluminum, paint flakes, and other disintegrated, structural and electronic components. Equations-of-state and associated calculations of shock stresses for typical LDEF impacts into the gold and aluminum substrates suggest that substantial vaporization may have occurred during many of the impacts and is the reason why approximately 50 percent of all craters did not contain sufficient residue to permit analysis by the SEM-EDX technique. After converting the crater diameters into projectile sizes using encounter speeds typical for the trailing-edge and forward-facing (Row 11) directions, and accounting for normalized exposure conditions of the CME collectors, we derived the absolute and relative fluxes of specific projectile classes. The natural impactors encounter all LDEF pointing directions with comparable, modal frequencies suggesting compositional (and dynamic) homogeneity of the interplanetary-dust environment in near-Earth orbit.

Bernhard, Ronald P.; See, Thomas H.; Hoerz, Friedrich

1993-01-01

402

Carbon Dioxide (CO2) Retrievals from Atmospheric Chemistry Experiment (ACE) Solar Occultation Measurements  

NASA Technical Reports Server (NTRS)

The Atmospheric Chemistry Experiment ACE satellite (SCISAT-1) was launched into an inclined orbit on 12 August 2003 and is now recording high signal-to-noise 0.02 per centimeter resolution solar absorption spectra covering 750-4400 per centimeter (2.3-13 micrometers). A procedure has been developed for retrieving average dry air CO2 mole fractions (X(sub CO2)) in the altitude range 7-10 kilometers from the SCISAT-1 spectra. Using the N2 continuum absorption in a window region near 2500 per centimeter, altitude shifts are applied to the tangent heights retrieved in version 2.2 SCISAT-1 processing, while cloudy or aerosol-impacted measurements are eliminated. Monthly-mean XCO2 covering 60 S to 60 N latitude for February 2004 to March 2008 has been analyzed with consistent trends inferred in both hemispheres. The ACE XCO2 time series have been compared with previously-reported surface network measurements, predictions based on upper tropospheric aircraft measurements, and space-based measurements. The retrieved X(sub CO2) from the ACE-FTS spectra are higher on average by a factor of 1.07 plus or minus 0.025 in the northern hemisphere and by a factor of 1.09 plus or minus 0.019 on average in the southern hemisphere compared to surface station measurements covering the same time span. The ACE derived trend is approximately 0.2% per year higher than measured at surface stations during the same observation period.

Rinsland, Curtis P.; Chiou, Linda; Boone, Chris; Bernath, Peter

2010-01-01

403

Validation of NO2 and NO from the Atmospheric Chemistry Experiment (ACE)  

NASA Astrophysics Data System (ADS)

Vertical profiles of NO2 and NO have been obtained from solar occultation measurements by the Atmospheric Chemistry Experiment (ACE), using an infrared Fourier Transform Spectrometer (ACE-FTS) and (for NO2) an ultraviolet-visible-near-infrared spectrometer, MAESTRO (Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation). In this paper, the quality of the ACE-FTS version 2.2 NO2 and NO and the MAESTRO version 1.2 NO2 data are assessed using other solar occultation measurements (HALOE, SAGE II, SAGE III, POAM III, SCIAMACHY), stellar occultation measurements (GOMOS), limb measurements (MIPAS, OSIRIS), nadir measurements (SCIAMACHY), balloon-borne measurements (SPIRALE, SAOZ) and ground-based measurements (UV-VIS, FTIR). Time differences between the comparison measurements were reduced using either a tight coincidence criterion, or where possible, chemical box models. ACE-FTS NO2 and NO and the MAESTRO NO2 are generally consistent with the correlative data. The ACE-FTS and MAESTRO NO2 volume mixing ratio (VMR) profiles agree with the profiles from other satellite data sets to within about 20% between 25 and 40 km, with the exception of MIPAS ESA (for ACE-FTS) and SAGE II (for ACE-FTS (sunrise) and MAESTRO) and suggest a negative bias between 23 and 40 km of about 10%. MAESTRO reports larger VMR values than the ACE-FTS. In comparisons with HALOE, ACE-FTS NO VMRs typically (on average) agree to ±8% from 22 to 64 km and to +10% from 93 to 105 km, with maxima of 21% and 36%, respectively. Partial column comparisons for NO2 show that there is quite good agreement between the ACE instruments and the FTIRs, with a mean difference of +7.3% for ACE-FTS and +12.8% for MAESTRO.

Kerzenmacher, T.; Wolff, M. A.; Strong, K.; Dupuy, E.; Walker, K. A.; Amekudzi, L. K.; Batchelor, R. L.; Bernath, P. F.; Berthet, G.; Blumenstock, T.; Boone, C. D.; Bramstedt, K.; Brogniez, C.; Brohede, S.; Burrows, J. P.; Catoire, V.; Dodion, J.; Drummond, J. R.; Dufour, D. G.; Funke, B.; Fussen, D.; Goutail, F.; Griffith, D. W. T.; Haley, C. S.; Hendrick, F.; Höpfner, M.; Huret, N.; Jones, N.; Kar, J.; Kramer, I.; Llewellyn, E. J.; López-Puertas, M.; Manney, G.; McElroy, C. T.; McLinden, C. A.; Melo, S.; Mikuteit, S.; Murtagh, D.; Nichitiu, F.; Notholt, J.; Nowlan, C.; Piccolo, C.; Pommereau, J.-P.; Randall, C.; Raspollini, P.; Ridolfi, M.; Richter, A.; Schneider, M.; Schrems, O.; Silicani, M.; Stiller, G. P.; Taylor, J.; Tétard, C.; Toohey, M.; Vanhellemont, F.; Warneke, T.; Zawodny, J. M.; Zou, J.

2008-10-01

404

"Doing Chemistry."  

ERIC Educational Resources Information Center

Summarizes papers presented at the Sixth Biennial Conference on Chemical Education in the area of "Doing Chemistry," i.e., demonstrations and student experiments. A bibliography of 21 presented papers in this area is attached. (CS)

Journal of Chemical Education, 1981

1981-01-01

405

Catalytic Chemistry.  

ERIC Educational Resources Information Center

Describes an approach for making chemistry relevant to everyday life. Involves the study of kinetics using the decomposition of hydrogen peroxide by vegetable juices. Allows students to design and carry out experiments and then draw conclusions from their results. (JRH)

Borer, Londa; And Others

1996-01-01

406

Chemistry Notes.  

ERIC Educational Resources Information Center

Describes equipment, activities, and experiments useful in chemistry instruction, including among others, a rapid method to determine available chlorine in bleach, simple flame testing apparatus, and a simple apparatus demonstrating the technique of flash photolysis. (SK)

School Science Review, 1980

1980-01-01

407

Impacts of dust on regional tropospheric chemistry during the ACE-Asia experiment: A model study with observations  

Microsoft Academic Search

A comprehensive regional-scale chemical transport model, Sulfur Transport and Emissions Model 2001 (STEM-2K1), is employed to study dust outflows and their influence on regional chemistry in the high-dust Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) period, from 4-14 April 2001. In this period, dust storms are initialized in the Taklamagan and Gobi deserts because of cold air outbreaks, are transported

Youhua Tang; Gregory R. Carmichael; Gakuji Kurata; Itsushi Uno; Rodney J. Weber; Chul-Han Song; Sarath K. Guttikunda; Jung-Hun Woo; David G. Streets; Cao Wei; Antony D. Clarke; Barry Huebert; Theodore L. Anderson

2004-01-01

408

Atmospheric Chemistry Experiment (ACE) Arctic stratospheric measurements of NOx during February and March 2004: Impact of intense solar flares  

Microsoft Academic Search

Solar occultation measurements recorded in the Arctic by the Atmospheric Chemistry Experiment (ACE) Fourier transform spectrometer show elevated volume mixing ratios of NO and NO2 in the upper stratosphere from mid-February to late March 2004. Mixing ratios of NO exceeded 1.3 ppmv (10-6 parts per million by volume) during mid-February and are higher than any values previously reported in the

Curtis P. Rinsland; Chris Boone; Ray Nassar; Kaley Walker; Peter Bernath; John C. McConnell; Linda Chiou

2005-01-01

409

The Oil Drop Experiment: A Rational Reconstruction of the Millikan-Ehrenhaft Controversy and Its Implications for Chemistry Textbooks  

NASA Astrophysics Data System (ADS)

Research in science education has recognized the importance of history and philosophy of science. Given this perspective, it is important to analyze how general chemistry textbooks interpret Millikan's oil drop experiment. This study has the following objectives: (a) elaboration of a history and philosophy of science framework based on a rational reconstruction of experimental observations that led to the Millikan-Ehrenhaft controversy; (b) formulation of six criteria based on the framework, which could be useful in the evaluation of chemistry textbooks; and (c) evaluation of 31 chemistry textbooks based on the criteria. Results obtained showed that most textbooks lacked a history and philosophy of science framework and did not deal adequately with the following aspects. (a) The Millikan-Ehrenhaft controversy can open a new window for students, demonstrating how two well-trained scientists can interpret the same set of data in two different ways. (b) Millikan's perseverance with his guiding assumption shows how scientists can overcome difficulties with anomalous data. (c) Millikan's methodology illustrates what modern philosophers of science consider important issues of falsification, confirmation, and suspension of disbelief. (d) The experiment is difficult to perform even today, owing to the incidence of a series of variables. (e) Millikan's major contribution consists of discovering the experiment to provide confirmation for the elementary electrical charge.

Niaz, Mansoor

2000-05-01

410

Incorporation of the CrossFire Beilstein Database into the Organic Chemistry Curriculum at the Royal Danish School of Pharmacy  

NASA Astrophysics Data System (ADS)

The CrossFire Beilstein database has been incorporated into the organic chemistry curriculum at the Royal Danish School of Pharmacy as a powerful pedagogic tool. During a laboratory course in organic synthesis the database enables the students to get comprehensive overviews of known synthetic methods for a given compound. During a laboratory course in identification and as a part of an applied course in organic spectroscopy the students use the database for obtaining lists of all recorded isomeric compounds, facilitating an exhaustive identification. The main entrances for identification purposes are molecular formulas deduced either from titrations or from mass spectra combined with partial structures identified by chemical tests, or by interpretation of spectra. Thus, identifications made using the CrossFire Beilstein database will exclude some possibilities and point to correct structures from a selection of existing compounds. This appears to help the learning process considerably.

Brøgger Christensen, S.; Franzyk, Henrik; Frølund, Bente; Jaroszewski, Jerzy W.; Stærk, Dan; Vedsø, Per

2002-06-01

411

Greener "Solutions" for the Organic Chemistry Teaching Lab: Exploring the Advantages of Alternative Reaction Media  

ERIC Educational Resources Information Center

A major approach for implementing green chemistry is the discovery and development of synthetic strategies that reduce the quantity of solvent needed, eliminate it altogether, or rely on new reaction media. An increasing number of examples have demonstrated that greener reaction solvents or media can enhance performance as well as reduce hazard.…

McKenzie, Lallie C.; Huffman, Lauren M.; Hutchison, James E.; Rogers, Courtney E.; Goodwin, Thomas E.; Spessard, Gary O.

2009-01-01

412

SELF-ASSEMBLING AMPHIPHILIC MOLECULES: A POSSIBLE LINKAGE BETWEEN INTERSTELLAR CHEMISTRY AND METEORITIC ORGANICS. S. A.  

E-print Network

SELF-ASSEMBLING AMPHIPHILIC MOLECULES: A POSSIBLE LINKAGE BETWEEN INTERSTELLAR CHEMISTRY by ionizing radiation [2,3]. Here we discuss the production of amphiphilic materials that can spon- taneously,5,6]. The presence of amphiphilic molecules is further con- firmed by surface tension measurements. These spe- cies

413

An Overview of the Lightning - Atmospheric Chemistry Aspects of the Deep Convective Clouds and Chemistry (DC3) Experiment  

NASA Astrophysics Data System (ADS)

Some of the major goals of the DC3 experiment are to determine the contribution of lightning to NOx (= NO + NO2) in the anvils of observed thunderstorms, examine the relationship of lightning NOx production to flash rates and to lightning channel lengths, and estimate the relative production per flash for cloud-to-ground flashes and intracloud flashes. In addition, the effects of lightning NOx production on photochemistry downwind of thunderstorms is also being examined. This talk will survey the observation types that were conducted during DC3 relevant to these goals and provide an overview of the analysis and modeling techniques, which are being used to achieve them. Observations of NOx were made on three research aircraft during DC3 (the NCAR G-V, the NASA DC-8, and the DLR Falcon) in flights through storm anvils in three study regions (NE Colorado, Central Oklahoma to West Texas, and northern Alabama) where lightning mapping arrays (LMAs) and radar coverage were available. Analysis techniques include initial comparisons of the aircraft NOx observations in storm anvils relative to flash rates, and calculations of the flux of NOx through the anvils, which are combined with observed flash rates to estimate storm-average lightning NOx production per flash. We plan to run the WRF-Chem model for cloud-resolved simulations of selected observed storms during DC3. Detailed lightning information from the LMAs (flash rates and flash lengths as a function of time and vertical distributions of flash channel segments) will be input to the model along with assumptions concerning NOx production per CG flash and per IC flash. These assumptions will be tested through comparisons with the aircraft NOx data from anvil traverses. In addition, a specially designed retrieval method for lightning NO2 column amounts from the OMI instrument on NASA's Aura satellite has been utilized to estimate NO2 over the region affected by selected DC3 storms. Combined with NOx to NO2 ratios from the aircraft data and WRF-Chem model and observed flash rates, average NOx production per flash can be estimated. Ozone production downwind of observed storms can be estimated from the WRF-Chem simulations and evaluated with the measured ozone on the downwind flights.

Pickering, K. E.; Barth, M. C.; Cummings, K.; Bucsela, E. J.; Allen, D. J.; Weinheimer, A. J.; Ryerson, T. B.; Huntrieser, H.; Bruning, E. C.; MacGorman, D. R.; Biggerstaff, M. I.; Krehbiel, P. R.; Thomas, R. J.; Rutledge, S. A.; Koshak, W. J.; Carey, L. D.

2012-12-01

414

4,5-Diphenyl-1-methylimidazole: An Undergraduate Laboratory Experiment.  

ERIC Educational Resources Information Center

Background information and procedures used are provided for the synthesis of 4,5-diphenyl-methylimidazole. This experiment on the chemistry of heterocycles is ideally suited for beginning undergraduate organic chemistry students. (JN)

Anastas, Paul T.; And Others

1985-01-01

415

Reaction mechanisms for the limited reversibility of Li–O 2 chemistry in organic carbonate electrolytes  

Microsoft Academic Search

The Li–O2 chemistry in nonaqueous liquid carbonate electrolytes and the underlying reason for its limited reversibility was systematically investigated. X-ray diffraction data showed that regardless of discharge depth lithium alkylcarbonates (lithium propylenedicarbonate (LPDC), or lithium ethylenedicarbonate (LEDC), with other related derivatives) and lithium carbonate (Li2CO3) are constantly the main discharge products, while lithium peroxide (Li2O2) or lithium oxide (Li2O) is

Wu Xu; Kang Xu; Vilayanur V. Viswanathan; Silas A. Towne; John S. Hardy; Jie Xiao; Zimin Nie; Dehong Hu; Deyu Wang; Ji-Guang Zhang

2011-01-01

416

Organization and Analysis of Data from the Qweak Experiment  

NASA Astrophysics Data System (ADS)

The Qweak experiment, which was conducted at the Thomas Jefferson National Accelerator Facility in a collaboration consisting of over twenty institutions, measured the small parity violating asymmetry occurring in elastic e-p scattering at low four-momentum transfer. This asymmetry will be used to calculate a precise value for the proton's weak charge. The Standard Model firmly predicts this weak charge based on the running of the weak mixing angle from the Z0 pole (where it is anchored by precise measurements) down to low energies. Through testing this prediction the Qweak experiment hopes to either constrain or reveal possible new physics beyond the Standard Model. Because of the small size of the predicted asymmetry and the precise nature of the measurement, over 2000 hours of data were taken. In order to help organize and store this data, a database has been implemented containing averages over sets of this data. It must be organized in such a way as to allow the quick and easy retrieval of data by collaborators with minimal knowledge of the database language. Tools for aggregating and expanding parts of this database as well as data analysis will be discussed.

Cargill, Dan; Spayde, Damon

2013-04-01

417

Developments and plans for new drifting balloon experiments in the Chemistry-Aerosol Mediterranean Experiment (ChArMEx) project  

NASA Astrophysics Data System (ADS)

ChArMEx (the Chemistry-Aerosol Mediterranean Experiment; http://charmex.lsce.ipsl.fr) is a new integrated project which aims at an assessment of the present state of the atmospheric environment in the Mediterranean basin, of its impacts on air quality, regional climate and marine biogeochemistry, and of their evolution in a regional context of intense climate change and increasing anthropogenic pressure. The Mediterranean is indeed characterized by a long dry and sunny season with high concentrations of aerosols and gaseous pollutants such as ozone. ChArMEx plans large international coordinated field campaigns with surface stations and airborne platforms including drifting balloons for studying the ageing of continental air masses transported over the basin. We are willing to deploy two types of balloons: (i) The Aeroclipper is a low altitude streamlined balloon drifting at 50 m over the sea surface and equipped with a cable and a guide-rope in contact with the surface ocean. It moves on a quasi-Lagrangian trajectory depending on the surface wind and marine current. Its instru-mentation is distributed on one atmospheric gondola and one oceanic gondola with the aim to measure surface physical parameters (air and sea surface temperatures, wind, pressure and humidity) in order to derive turbulent fluxes of moisture, heat and momentum. (ii) The BPCL is a long duration super-pressure balloon designed to drift in the atmospheric boundary layer. It moves on a quasi-Lagrangian trajectory at an adjustable constant atmo-spheric density level which altitude ranges between a few hundreds of m and about 3 km. Its instrumentation includes air pressure, temperature and humidity. Both balloon types are equipped with a positioning system and a data transmission system. In addition we are developing new small instruments to be integrated in the payload of these two balloon types. This includes radiation sensors to measure visible and infrared fluxes, an optical particle counter/sizer (see presentation by Renard et al.), and a modified electrochemical ozone sonde. This new instrumentation will allow us to perform original Lagrangian type measurements covering day-night cycles in order to monitor the evolution of ozone and aerosols in ageing continental air masses circulating over the sea, and eventually the influence of aerosols on the sea surface evaporation. Based on trajectory computations, the lifetime of the flights over the basin should be of a few days. Balloons should be launched from the northern and southern shores of the western Mediterranean to follow polluted and Saharan air masses, respectively. A first test campaign with BPCL will be performed in the region of Marseille-Fos-Berre in summer 2011. The main campaigns are planned in summer 2012 and spring 2013 in the western Mediterranean.

Dulac, François; Durand, Pierre; Verdier, Nicolas; Renard, Jean-Baptiste; Mallet, Marc; Thouret, Valérie; Attié, Jean-Luc

418

Quantitative Ultrasound-Assisted Extraction for Trace-Metal Determination: An Experiment for Analytical Chemistry  

ERIC Educational Resources Information Center

Ultrasound-assisted extraction (UAE) is introduced to upper-level analytical chemistry students as a simple strategy focused on sample preparation for trace-metal determination in biological tissues. Nickel extraction in seafood samples and quantification by electrothermal atomic absorption spectrometry (ETAAS) are carried out by a team of four…

Lavilla, Isela; Costas, Marta; Pena-Pereira, Francisco; Gil, Sandra; Bendicho, Carlos

2011-01-01

419

The use of food in chemistry experiments to engage and enrich the teaching in the classroom  

Microsoft Academic Search

Students often gain more knowledge out of hands on work. Labs and demonstrations increase knowledge often more than the book work and notes because they motivate interest and provide real world application. In an effort to incorporate labs into chemistry I have developed a unit centered on food in order to teach a variety of concepts and lab techniques to

Brian Michael Topping

2010-01-01

420

Space Resources for Teachers: Chemistry; Including Suggestions for Classroom Activities and Laboratory Experiments.  

ERIC Educational Resources Information Center

This publication is composed of 10 units, each based on an area of space science and technology in which chemistry plays an important role. Each resource unit can be used independently of the others and materials can be selected from within a unit. The materials range in difficulty from the junior high level of understanding to those that will…

Lawrence, Richard M.

421

Challenges in Teaching "Colloid and Surface Chemistry"--A Danish Experience  

ERIC Educational Resources Information Center

Seven years ago we were asked, as one of our first teaching duties at the Technical University of Denmark (DTU), to teach a 5 ECTS point course on "Colloid and Surface Chemistry". The topic is itself at the same time exciting and demanding, largely due to its multidisciplinary nature. Several "local" requirements posed additional challenges. The…

Kontogeorgis, Georgios M.; Vigild, Martin E.

2009-01-01

422

The Evolution of a Green Chemistry Laboratory Experiment: Greener Brominations of Stilbene  

ERIC Educational Resources Information Center

The use of green metrics to compare three bromination laboratory procedures demonstrates the effectiveness of an incremental greening process for chemistry curricula. Due to this process, the bromination of alkenes can be introduced to students through the use of a safe, effective, modern practice.

McKenzie, Lallie C.; Huffman, Lauren M.; Hutchison, James E.

2005-01-01

423

Sugar-Cube Science: An Economical Inquiry Experiment for High School Chemistry  

ERIC Educational Resources Information Center

Many first-year chemistry students have memorized the steps of the "scientific method" and can recite them without any prompting. But when introduced to controlled, independent, and dependent variables, they hit a brick wall. Therefore, the author of this article created a lesson that allows students to determine the fastest way to dissolve a…

Smith, Jennifer

2010-01-01

424

Carbon oxidation state as a metric for describing the chemistry of atmospheric organic aerosol  

SciTech Connect

A detailed understanding of the sources, transformations, and fates of organic species in the environment is crucial because of the central roles that organics play in human health, biogeochemical cycles, and Earth's climate. However, such an understanding is hindered by the immense chemical complexity of environmental mixtures of organics; for example, atmospheric organic aerosol consists of at least thousands of individual compounds, all of which likely evolve chemically over their atmospheric lifetimes. Here we demonstrate the utility of describing organic aerosol (and other complex organic mixtures) in terms of average carbon oxidation state (OSC), a quantity that always increases with oxidation, and is readily measured using state-of-the-art analytical techniques. Field and laboratory measurements of OSC , using several such techniques, constrain the chemical properties of the organics and demonstrate that the formation and evolution of organic aerosol involves simultaneous changes to both carbon oxidation state and carbon number (nC).

Massachusetts Institute of Technology; Kroll, Jesse H.; Donahue, Neil M.; Jimenez, Jose L.; Kessler, Sean H.; Canagaratna, Manjula R.; Wilson, Kevin R.; Altieri, Katye E.; Mazzoleni, Lynn R.; Wozniak, Andrew S.; Bluhm, Hendrik; Mysak, Erin R.; Smith, Jared D.; Kolb, Charles E.; Worsnop, Douglas R.

2010-11-05

425

A New GC-MS Experiment for the Undergraduate Instrumental Analysis Laboratory in Environmental Chemistry: Methyl-t-butyl Ether and Benzene in Gasoline  

Microsoft Academic Search

With the recent ACS approval of an option in environmental chemistry at the undergraduate level, there is a need for new experiments that illustrate fundamental principles of instrumental analysis in the context of environmental chemistry. We describe an experiment that utilizes combined gas chromatography-mass spectrometry (GC-MS) in the qualitative and quantitative analysis of methyl tert-butyl ether (MTBE) and benzene in

Dinh T. Quach; Nancy A. Ciszkowski; Barbara J. Finlayson-Pitts

1998-01-01

426

Implementing POGIL in the Lecture and the Science Writing Heuristic in the Laboratory--Student Perceptions and Performance in Undergraduate Organic Chemistry  

ERIC Educational Resources Information Center

This study investigated the possible connection between effective laboratory activities and student performance on lecture exams. In a traditional undergraduate organic chemistry course for non-science majors, students could predict the products of organic reactions, but struggled to provide reaction mechanisms for those same reactions, despite…

Schroeder, Jacob D.; Greenbowe, Thomas J.

2008-01-01

427

Predicting Complex Organic Mixture Atmospheric Chemistry Using Computer-Generated Reaction Models  

Microsoft Academic Search

New measurement and chemical characterization technologies now offer unprecedented capabilities for detecting and describing atmospheric organic matter at the molecular level. As a result, very detailed and extensive chemical inventories are produced routinely in atmospheric field measurements of organic compounds found in the vapor and condensed phases (particles, cloud and fog droplets). Hundreds of organic compounds can constitute the complex

M. T. Klein; L. J. Broadbelt; M. A. Mazurek

2001-01-01

428

Ligand chemistry of titania precursor affects transient photovoltaic behavior in inverted organic solar cells  

E-print Network

transient photovoltaic behavior in inverted organic solar cells Jong Bok Kim,1,a) Seokhoon Ahn,2,b) Seok Ju significantly affect the device performance of organic solar cells. Here, we compare two common precursors electron traps. Furthermore, organic solar cells with titania electron transport layers prepared

Hone, James

429

Chemistry Tutorials  

NSDL National Science Digital Library

The California State University Stanislaus developed these interactive chemistry Web tutorials to assist college students in mass spectrometry, proton NMR chemical shifts, and more. With the many animations and figures, visitors will find assistance with the subtraction and absorption of light and with infrared absorption frequencies for numerous compounds. The titration tutorials simulate laboratory experiments without the hazards of dealing with chemicals. Students will also find a very informative lesson describing how to use Excel to record and analyze their chemistry data.

430

How thermal curing of an organic paper coating changes topography, chemistry, and wettability.  

PubMed

Celluloses are preferred renewable substrates, but hydrophilicity and porosity disfavor their water resistance. We present here an ecofriendly application of imidized nanoparticles and a method to flexibly tune the surface wettability of papers. The soft nanostructured coating is sensitive to thermal curing, which affects both the surface chemistry and morphology. The thermal stability of the coating is first investigated with conventional and modulated differential scanning calorimetry, revealing influences of the imide content and an endotherm reaction below the glass transition temperature at 120-150 °C. The latter is studied in detail for an appropriate selection of the copolymer precursors. According to diffuse reflection infrared spectroscopy, Raman spectroscopy, and UV/vis spectroscopy, the endotherm corresponds to an imidization reaction. The morphology of the coatings is followed at various scale levels by contactless roughness measurements and atomic force microscopy. Finally, the experimental values are fitted to the parameters of the Wenzel wetting model, and so-called calibration curves for the relation between contact angles, surface roughness, and surface chemistry are presented. They allow the prediction of the water contact angle of coated papers from the hydrophilic to the hydrophobic range, with a maximum in hydrophobicity after increasing the imide content at 120-150 °C curing. PMID:21650187

Samyn, Pieter; Schoukens, Gustaaf; Vonck, Leo; Stanssens, Dirk; Van den Abbeele, Henk

2011-07-01

431

Micro-abrasion package capture cell experiment on the trailing edge of LDEF: Impactor chemistry and whipple bumper shield efficiencies  

NASA Technical Reports Server (NTRS)

Four of the eight available double layer microparticle capture cells, flown as the experiment A0023 on the trailing (West) face of LDEF, have been extensively studied. An investigation of the chemistry of impactors has been made using SEM/EDX techniques and the effectiveness of the capture cells as bumper shields has also been examined. Studies of these capture cells gave positive EDX results, with 53 percent of impact sites indicating the presence of some chemical residues, the predominant residue identified as being silicon in varying quantities.

Fitzgerald, Howard J.; Yano, Hajime

1995-01-01

432

MAC 560 --Tropospheric Chemistry I Spring, 2009  

E-print Network

chemistry · to learn the atmospheric chemistry behind well-known phenomena such as smog, acid rain.3. Sulfur chemistry and acid rain 5.4. Nitrogen chemistry 5.5. Organic acids 5.6. Ecological and structural

Miami, University of

433

Chemistry Notes.  

ERIC Educational Resources Information Center

Describes some laboratory apparatus, chemistry experiments and demonstrations, such as a Kofler block melting point apparatus, chromatographic investigation of the phosphoric acid, x-ray diffraction, the fountain experiment, endothermic sherbet, the measurement of viscosity, ionization energies and electronic configurations. (GA)

School Science Review, 1978

1978-01-01

434

Positronium signature in organic liquid scintillators for neutrino experiments  

NASA Astrophysics Data System (ADS)

Electron antineutrinos are commonly detected in liquid scintillator experiments via inverse ? decay by looking at the coincidence between the reaction products: neutrons and positrons. Prior to positron annihilation, an electron-positron pair may form an orthopositronium (o-Ps) state, with a mean lifetime of a few nanoseconds. Even if the o-Ps decay is speeded up by spin-flip or pick-off effects, it may introduce distortions in the photon emission time distribution, crucial for position reconstruction and pulse shape discrimination algorithms in antineutrino experiments. Reversing the problem, the o-Ps-induced time distortion represents a new signature for tagging antineutrinos in liquid scintillator. In this article, we report the results of measurements of the o-Ps formation probability and lifetime for the most used solvents for organic liquid scintillators in neutrino physics (pseudocumene, linear alkyl benzene, phenylxylylethane, and dodecane). We characterize also a mixture of pseudocumene +1.5 g/l of 2,5-diphenyloxazole, a fluor acting as wavelength shifter. In the second part of the article, we demonstrate that the o-Ps-induced distortion of the scintillation photon emission time distributions represent an optimal signature for tagging positrons on an event by event basis, potentially enhancing the antineutrino detection.

Franco, D.; Consolati, G.; Trezzi, D.

2011-01-01

435

This paper is published as part of Faraday Discussions volume 145: Frontiers in Physical Organic Chemistry  

E-print Network

Ji, John H. Atherton and Michael I. Page, Faraday Discuss., 2010 DOI: 10.1039/b912261n InterrogationThis paper is published as part of Faraday Discussions volume 145: Frontiers in Physical Organic-water organic catalysis, enzyme catalysis, and single-molecule fluctuations R. A. Marcus, Faraday Discuss., 2010

Strathclyde, University of

436

A Green Multicomponent Reaction for the Organic Chemistry Laboratory: The Aqueous Passerini Reaction  

ERIC Educational Resources Information Center

Water is the ideal green solvent for organic reactions. However, most organic molecules are insoluble in it. Herein, we report a laboratory module that takes advantage of this property. The Passerini reaction, a three-component coupling involving an isocyanide, aldehyde, and carboxylic acid, typically requires [similar to] 24 h reaction times in…

Hooper, Matthew M.; DeBoef, Brenton

2009-01-01

437

Incorporation of Gas Chromatography-Mass Spectrometry into the Undergraduate Organic Chemistry Laboratory Curriculum  

ERIC Educational Resources Information Center

Gas chromatography-mass spectrometry (GC-MS) is a powerful analytical tool for detection, identification, and quantification of many volatile organic compounds. However, many colleges and universities have not fully incorporated this technique into undergraduate teaching laboratories despite its wide application and ease of use in organic

Giarikos, Dimitrios G.; Patel, Sagir; Lister, Andrew; Razeghifard, Reza

2013-01-01

438

Using a Premade Grignard Reagent to Synthesize Tertiary Alcohols in a Convenient Investigative Organic Laboratory Experiment  

ERIC Educational Resources Information Center

A commercially available Grignard reagent (3.0 M solution of phenyl magnesium bromide in ether) was used in a convenient Grignard synthesis in a second-year organic chemistry laboratory without any of the typical failures associated with the Grignard reaction. The reaction setup used oven-dried glassware and no extraordinary measures were taken to…

Berg, Michael A. G.; Pointer, Roy D.

2007-01-01

439

Modelling non-equilibrium secondary organic aerosol formation and evaporation with the aerosol dynamics, gas- and particle-phase chemistry kinetic multilayer model ADCHAM  

NASA Astrophysics Data System (ADS)

We have developed the novel Aerosol Dynamics, gas- and particle-phase chemistry model for laboratory CHAMber studies (ADCHAM). The model combines the detailed gas-phase Master Chemical Mechanism version 3.2 (MCMv3.2), an aerosol dynamics and particle-phase chemistry module (which considers acid-catalysed oligomerization, heterogeneous oxidation reactions in the particle phase and non-ideal interactions between organic compounds, water and inorganic ions) and a kinetic multilayer module for diffusion-limited transport of compounds between the gas phase, particle surface and particle bulk phase. In this article we describe and use ADCHAM to study (1) the evaporation of liquid dioctyl phthalate (DOP) particles, (2) the slow and almost particle-size-independent evaporation of ?-pinene ozonolysis secondary organic aerosol (SOA) particles, (3) the mass-transfer-limited uptake of ammonia (NH3) and formation of organic salts between ammonium (NH4+) and carboxylic acids (RCOOH), and (4) the influence of chamber wall effects on the observed SOA formation in smog chambers. ADCHAM is able to capture the observed ?-pinene SOA mass increase in the presence of NH3(g). Organic salts of ammonium and carboxylic acids predominantly form during the early stage of SOA formation. In the smog chamber experiments, these salts contribute substantially to the initial growth of the homogeneously nucleated particles. The model simulations of evaporating ?-pinene SOA particles support the recent experimental findings that these particles have a semi-solid tar-like amorphous-phase state. ADCHAM is able to reproduce the main features of the observed slow evaporation rates if the concentration of low-volatility and viscous oligomerized SOA material at the particle surface increases upon evaporation. The evaporation rate is mainly governed by the reversible decomposition of oligomers back to monomers. Finally, we demonstrate that the mass-transfer-limited uptake of condensable organic compounds onto wall-deposited particles or directly onto the Teflon chamber walls of smog chambers can have a profound influence on the observed SOA formation. During the early stage of the SOA formation the wall-deposited particles and walls themselves serve as an SOA sink from the air to the walls. However, at the end of smog chamber experiments the semi-volatile SOA material may start to evaporate from the chamber walls. With these four model applications, we demonstrate that several poorly quantified processes (i.e. mass transport limitations within the particle phase, oligomerization, heterogeneous oxidation, organic salt formation, and chamber wall effects) can have a substantial influence on the SOA formation, lifetime, chemical and physical particle properties, and their evolution. In order to constrain the uncertainties related to these processes, future experiments are needed in which as many of the influential variables as possible are varied. ADCHAM can be a valuable model tool in the design and analysis of such experiments.

Roldin, P.; Eriksson, A. C.; Nordin, E. Z.; Hermansson, E.; Mogensen, D.; Rusanen, A.; Boy, M.; Swietlicki, E.; Svenningsson, B.; Zelenyuk, A.; Pagels, J.

2014-08-01

440

Synthesis of a Self-Healing Polymer Based on Reversible Diels-Alder Reaction: An Advanced Undergraduate Laboratory at the Interface of Organic Chemistry and Materials Science  

ERIC Educational Resources Information Center

This laboratory experiment exposes students to the chemistry of self-healing polymers based on a Diels-Alder reaction. Students accomplish a multistep synthesis of a monomer building block and then polymerize it to form a cross-linked polymer. The healing capability of the polymer is verified by differential scanning calorimetry (DSC) experiments.…

Weizman, Haim; Nielsen, Christian; Weizman, Or S.; Nemat-Nasser, Sia

2011-01-01

441

Session on coupled atmospheric/chemistry coupled models  

NASA Technical Reports Server (NTRS)

The session on coupled atmospheric/chemistry coupled models is reviewed. Current model limitations, current issues and critical unknowns, and modeling activity are addressed. Specific recommendations and experimental strategies on the following are given: multiscale surface layer - planetary boundary layer - chemical flux measurements; Eulerian budget study; and Langrangian experiment. Nonprecipitating cloud studies, organized convective systems, and aerosols - heterogenous chemistry are also discussed.

Thompson, Anne

1993-01-01

442

Carbon oxidation state as a metric for describing the chemistry of atmospheric organic aerosol  

E-print Network

A detailed understanding of the sources, transformations and fates of organic species in the environment is crucial because of the central roles that they play in human health, biogeochemical cycles and the Earth's climate. ...

Kroll, Jesse

443

Real World of Industrial Chemistry: Ethylene: The Organic Chemical Industry's Most Important Building Block.  

ERIC Educational Resources Information Center

The value of ethylene, as the organic chemical industry's most important building block, is discussed. The discussion focuses on the source of ethylene, its various forms and functions, and the ways in which the forms are made. (SA)

Fernelius, W. Conrad, Ed.; And Others

1979-01-01

444

Organometallic Chemistry of Molybdenum.  

ERIC Educational Resources Information Center

Suggests ways to avoid some of the problems students have learning the principles of organometallic chemistry. Provides a description of an experiment used in a third-year college chemistry laboratory on molybdenum. (TW)

Lucas, C. Robert; Walsh, Kelly A.

1987-01-01

445

Simulation of organic molecule formation in solar system environments-The Miller-Urey Experiment in Space project overview  

NASA Astrophysics Data System (ADS)

The Miller-Urey Experiment in space (MUE) investigates the formation of potential prebiotic organic compounds in the early solar system environment. The MUE experiment will be sent to and retrieved from the International Space Station (ISS), where it will be performed inside the Microgravity Science Glovebox (MSG). The goal of this space experiment is to understand prebiotic reactions in microgravity by simulating environments of the early solar nebula. The dynamic environment of the solar nebula with the simultaneous presence of gas, particles, and energetic processes, including shock waves, lightning, and radiation may trigger a rich organic chemistry leading to organic molecules. These environments will be simulated in six fabricated vials containing various gas mixtures as well as solid particles. Two gas mixture compositions will be tested and subjected to continuous spark discharges for 48, 96, and 192 hours. Silicate particles will serve as surfaces on which thin water ice mantles can accrete. The particles will move repeatedly through a high-voltage spark discharge in microgravity, enabling chemical re-actions analogous to the original Miller-Urey experiment. The experiment will be performed at low temperatures (-5 C), slowing hydrolysis and improving chances of detection of interme-diates, initial products, and their distributions. Executing the Miller-Urey experiment in the space environment (microgravity) allows us to simulate conditions that could have prevailed in the energetic early solar nebula and provides insights into the chemical pathways that may occur in forming planetary systems. Analysis will be performed post-flight using chemical analytical methods. The anticipated results will provide information about chemical reaction pathways to form organic compounds in space environment, emphasizing abiotic chemical pathways and mechanisms that could have been crucial in the formation of biologically relevant compounds such as amino acids and nucleobases, basic constituents common to life on Earth.

Kotler, J. Michelle; Ehrenfruend, Pascale; Botta, Oliver; Blum, Jurgen; Schrapler, Rainer; van Dongen, Joost; Palmans, Anja; Sephton, Mark A.; Martins, Zita; Cleaves, Henderson J.; Ricco, Antonio

446

Organic chemistry of fluids from sediment-buried young basement: discrete sampling from ODP borehole 1301A & 1025C  

NASA Astrophysics Data System (ADS)

Hydrothermal systems profoundly influence seawater chemistry. However, the extent to which hydrothermal systems impact the quantity and the quality of the deep ocean dissolved organic carbon (DOC) pool remains unclear. To study the organic chemistry within sedimented ridge flank basement aquifers, discrete low temperature (~65°C & ~40°C) basement fluids were collected from Integrated Ocean Drilling Program boreholes via Circulation Obviation Retrofit Kit (CORK) observatories at 1301A (47°45N, 127°45W) and 1025C (47°53N, 128°39W) on the eastern flank of Juan de Fuca Ridge. The basement age is 1.24 Ma and 3.5 Ma at 1025C and 1301A, respectively. Basement fluids were collected using a new clean pumping system (Mobile Pump Valve Unit, or MPVU) and stored in acid-cleaned 60 L Large Volume Tedlar Bags (LVBS). A stainless steel fluid delivery line extends from the basement to the seafloor at 1301A; whereas fluids rise up the middle of the iron casing at 1025C. Here, concentration and preliminary characterization of the DOC will be presented, including labile organic components such as dissolved free and combined amino acids (DFAA & DCAA) and low molecular weight organic acids (LMW-OA). Our data show that compared to seawater levels, the DOC concentration in the younger basement fluid (1025C) was about one-half and in the older (1031A) was less than one-third. Relative to bottom seawater, the basement fluids are also depleted in SO42-, PO43-, NO3- and NO2-, but enriched in NH4+, H2S, Mn and Fe. Microbially mediated reduction of nitrate, sulfate, iron, and manganese and an array of heterotrophic metabolisms may explain these observations. Phylogenic trees based on 16S rRNA gene sequences from borehole 1301A fluids further support the presence of chemolithoautotrophic and heterotrophic organisms. Our preliminary results show that some dissolved free amino acids were slightly enriched in the 1301A basement fluid relative to bottom seawater. Thermodynamic calculations suggest that the basement environment is not conducive to the abiotic formation of these amino acids. Hence, these amino acids were likely produced biologically in situ, or imported from external source such as diffusion of sediment porewater across the sediment-basement interface. The low molecular weight organic acids were below detection limit (<0.5 µM) in both 1301A basement fluid and bottom seawater. Presumably, the production of these organic acids was coupled to their rapid removal via heterotrophic consumption. The organic compositions will be discussed with respect to the availability of organic substrates and energy sources for heterotrophic organisms in the basement environments. The data will also be used for thermodynamic calculations to constrain possible metabolic pathways in this environment.

Lin, H.; Cowen, J. P.; Amend, J. P.; Albert, D. B.; Glazer, B. T.; Rappe, M.; Jungbluth, S.; Matzinger, M.

2010-12-01

447

Impact of isoprene and nitrogen oxides on O3 chemistry at the local and the regional scale : the ESCOMPTE experiment  

NASA Astrophysics Data System (ADS)

Concentrations of nitrogen oxides (NOx = NO+NO2) and volatile organic compounds (VOCs) play a crucial role in the atmospheric chemistry through the production-destruction of tropospheric O3. In rural areas, NOx concentrations are much lower than in urban areas, whereas VOCs emissions can be relatively high. This is due to a relative longer residence time of VOCs, and to the substantial contribution of Biogenic VOCs (BVOCs) representing more than 85% of all the VOCs emitted at the Earth surface (half of it being isoprene). For these reasons, O3 production in rural areas is most of the time NOx-limited. Taking into account biogenic emissions of isoprene in global scale atmospheric chemistry modeling adds from 10 to 40% to the ozone produced when compared to the same simulation without isoprene. This suggests that BVOCs and NOx emissions must be accounted for in models of atmospheric pollution forecasting at local and regional scales. In this study, we present a sensitivity analysis on the impact of the isoprene and nitrogen oxides emissions at the local and the regional scale. This study is done from data collected during the ESCOMPTE campaign which took place in June and July 2001 in the Marseille region (Southwest France) characterized by both strong natural and anthropogenic sources of trace gases. Isoprene emission experimental data from a Quercus Pubescens Mediterranean forest are used to constrain the 1Dz Soil-Vegetation-Atmospheric-Transfer ISBA model. This SVAT is used in the 3D MESO-NH-Chemistry model to simulate scenarios of pollution at the regional scale including the measured biogenic source for isoprene, and GENEMIS anthropogenic sources for other trace gases. To focus on the chemistry aspect of these simulations, the atmospheric dynamics are set to an "ideal" configuration. We have investigated the impact of the relative position and distance between the biogenic and anthropogenic sources on the O3 budget. According to this, and to the intensity of the anthropogenic sources, isoprene emissions impact can become relatively significant in terms of O3 concentrations. O3 production is clearly linked with the different photochemical regime, with limitations for high COV:NOx (>20 -NOx limited) and low (<4 -COV limited) ratios. We performed an other sensitivity analysis on biogenic NOx emissions from crops, and their impact on O3 budget using a 1Dz model SURFATM. This model is based on an approach describing atmospheric exchanges with resistances (Choudhury and Monteith, 1988 ; Nemitz, 1998). Similarly to the ISBA scheme, SURFATM simulates the surface energy budget and the atmosphere-biosphere exchange of chemical species. We developed the model by including the basic NOx-O3 chemistry above and below the canopy. Ozone fluxes were simulated by the model constrained with ESCOMPTE experimental data performed in a maize field. The more detailed description of vegetation, and the inclusion of the chemistry scheme allowed us to have a better representation of ozone fluxes at the canopy scale. SURFATM will then be used in MESO-NH-Chemistry to simulate the interaction between a rural and an urban (or industrial) plume, as we did for isoprene. The last step will be to include the biogenic sources for isoprene and nitrogen oxides, and to perform new scenarios of pollution at the local or regional scale.

Cortinovis, J.; Solmon, F.; Personne, E.; Serça, D.; Rosset, R.

2003-04-01

448

Chemistry of organic carbon in soil with relationship to the global carbon cycle  

SciTech Connect

Various ecosystem disturbances alter the balances between production of organic matter and its decomposition and therefore change the amount of carbon in soil. The most severe perturbation is conversion of natural vegetation to cultivated crops. Conversion of natural vegetation to cultivated crops results in a lowered input of slowly decomposing material which causes a reduction in overall carbon levels. Disruption of soil matrix structure by cultivation leads to lowered physical protection of organic matter resulting in an increased net mineralization rate of soil carbon. Climate change is another perturbation that affects the amount and composition of plant production, litter inputs, and decomposition regimes but does not affect soil structure directly. Nevertheless, large changes in soil carbon storage are probable with anticipated CO2 induced climate change, particularly in northern latitudes where anticipated climate change will be greatest (MacCracken and Luther 1985) and large amounts of soil organic matter are found. It is impossible, given the current state of knowledge of soil organic matter processes and transformations to develop detailed process models of soil carbon dynamics. Largely phenomenological models appear to be developing into predictive tools for understanding the role of soil organic matter in the global carbon cycle. In particular, these models will be useful in quantifying soil carbon changes due to human land-use and to anticipated global climate and vegetation changes. 47 refs., 7 figs., 2 tabs.

Post, W.M. III

1988-01-01

449

UNIVERSITY OF CALIFORNIA, SANTA CRUZ DEPARTMENT OF CHEMISTRY AND BIOCHEMISTRY  

E-print Network

UNIVERSITY OF CALIFORNIA, SANTA CRUZ DEPARTMENT OF CHEMISTRY AND BIOCHEMISTRY Lecturer Pool The Department of Chemistry and Biochemistry at the University of California, Santa Cruz, invites applications specialty within chemistry and biochemistry (including general chemistry, organic chemistry, inorganic

California at Santa Cruz, University of

450

Organizing Science Popularization and Teacher Training Workshops : A Nigerian Experience  

NASA Astrophysics Data System (ADS)

Funding for science popularization has become a huge challenge in recent times especially for developing countries like Nigeria. However, a change in the school system from the 6-3-3-4 system (6 years primary, 3 years Junior secondary, 3year senior secondary, and 4 years tertiary education) to the 9-3-4 system ( 9 years junior basic, 3 years secondary, and 4 tertiary education) has made it even more convenient to strategically target the students through their teachers to attain the desired quality of education since the introduction of space science into the curriculum at the primary and secondary levels. Considering the size of Nigeria, there Is need for a shift in paradigm for sourcing resources to tackle this deficiency in a sustainable manner. Recently a teacher training and science popularization workshop was organized as a first in a series of subsequent workshops geared towards having a sustainable means of popularizing Science in Nigeria. Principally, the key lies in the partnership with the colleges of education which produce the teachers for primary schools in addition to the usual governmental actions. Experiences from this workshop will be enumerated with the hope of inspiring the same success in similar societies.

Okpala, Kingsley; Okere, Bonaventure

451

Atmospheric Chemistry  

NSDL National Science Digital Library

This set of links provides access to resources on atmospheric chemistry, especially acid deposition, air pollution, and air quality. The sites include personal and government pages, universities and research groups, non-governmental organizations and meetings, and products and services. There are also links to related search topics.

452

Formate dehydrogenase--a biocatalyst with novel applications in organic chemistry.  

PubMed

In the field of industrial biocatalysis, formate dehydrogenase (FDH) is well established, in particular for its broad application in cofactor regeneration. Further applications have been limited by the enzyme's narrow range of substrates. These restrictions have been overcome now by the finding, that the enzyme is capable of selectively cleaving formic acid esters to the respective alcohol. Five homologous alkyl formates and phenyl formate as an aromatic ester were converted quantitatively by FDH from Candida boidinii in a batch reaction within 3 to 5 h. The substrates were turned irreversibly into carbon dioxide and the respective alcohol through hydride abstraction from the formyl group with full conversion. The mechanism shows parallels to hydrolysis reactions of the A(AC)1-type. K(M)-values and reactions rates of the tested formic acid esters display a tendency to higher conversion rates with increasing chain length. FDH emerged to be a superior deformylation catalyst compared to hydrolases as well as classical catalysts, as was shown by the selective deformylation of 1-acetoxy-4-formoxy butane (92%) and 1,3-bis(3-formoxypropyl)tetramethyldisiloxane. In particular its capability to distinguish between formic acid esters and non-formic acid esters renders the method particularly suitable for protective group chemistry. Furthermore the completeness of deformylation allows for converting substrates highly incompatible with aqueous media like siloxanes within a few hours. PMID:21989535

Fröhlich, Peter; Albert, Kristin; Bertau, Martin

2011-10-26

453

Estimating the Analytical and Surface Enhancement Factors in Surface-Enhanced Raman Scattering (SERS): A Novel Physical Chemistry and Nanotechnology Laboratory Experiment  

ERIC Educational Resources Information Center

A novel laboratory experiment was successfully implemented for undergraduate and graduate students in physical chemistry and nanotechnology. The main goal of the experiment was to rigorously determine the surface-enhanced Raman scattering (SERS)-based sensing capabilities of colloidal silver nanoparticles (AgNPs). These were quantified by…

Pavel, Ioana E.; Alnajjar, Khadijeh S.; Monahan, Jennifer L.; Stahler, Adam; Hunter, Nora E.; Weaver, Kent M.; Baker, Joshua D.; Meyerhoefer, Allie J.; Dolson, David A.

2012-01-01

454

Determination of Solvent Effects on Keto-Enol Equilibria of 1,3-Dicarbonyl Compounds Using NMR: Revisiting a Classic Physical Chemistry Experiment  

ERIC Educational Resources Information Center

The use of proton NMR to determine the equilibrium position of tautomeric 1,3-dicarbonyl compounds in various solvents has been a classic physical chemistry experiment. We are presenting an expansion of the excellent description of this experiment by Garland, Shoemaker, and Nibler. Often the assumption is made that the keto tautomer is always the…

Cook, A. Gilbert; Feltman, Paul M.

2007-01-01

455

Experience and the arts: An examination of an arts-based chemistry class  

NASA Astrophysics Data System (ADS)

Many high school students are either intimidated or unmotivated when faced with science courses taught with a traditional teaching methodology. The focus of this study was the integration of the arts, specifically the Creative Arts Laboratory (CAL) approach, into the teaching methodology and assessment of a high school chemistry class, with particular interest in what occurs from the point of view of the students and the teacher throughout the integration. Using a case study design, research questions were developed that looked at the effects of arts-integration on the students and teacher in a high school chemistry class; what strategies of arts integration were viewed positively and negatively by the students and teacher; and what role the arts may play in the formation of a new approach to the high school science curriculum. The levels of student engagement and participation were changed and thusly viewed positively by both students and teacher. Specifically, group work that allowed students to choose various arts elements to depict chemistry concepts was considered mos