| Other Resources: 37 results |
Molecular Models of Antioxidants and Radicals William F. Coleman
This month's featured molecules come from the paper by John M. Berger, Roshniben J. Rana, Hira Javeed, Iqra Javeed, and Sandi L. Schulien (1) describing the use of DPPH to measure antioxidant activity. DPPH was one of the featured molecules in September 2007 (2) and the basics of antioxidant activity were introduced in last month's column (3). In addition, some of the other molecules in the paper are already in the featured molecules collection (4). The remaining structures in the Figure 1 and Table 1 of the paper have been added to the collection. All structures have been optimized at the 6-311G(D,P) level. These molecules suggest a number of possible student activities, some reminiscent of previous columns and some new. (R,R,R)-α-tocopherol is one of the molecules in the mixture that goes by the name vitamin E. These molecules differ in the substituents on the benzene ring and on whether or not there are alternating double bonds in the phytyl tail. In (R,R,R)-α-tocopherol the R's refer to the three chiral carbon atoms in tail while α refers to the substituents on the ring. (R,R,R)-α-Tocopherol is the form found in nature. An interesting literature problem would be to have students learn more about the vitamin E mixture and the differing antioxidant activity of the various constituents. Additionally they could be asked to explore the difference between the word natural as used by a chemist, and "natural" as used on vitamin E supplements. Can students find regulations governing the use of the term "natural"? Can they suggest alternative legislation, and defend their ideas? If students read about vitamin C they will discover that only L-ascorbic acid is useful in the body. It would be interesting to extend the experiment described in the Berger et al. paper (1) to include D-ascorbic acid. How do the antioxidant abilities of the enantiomers, as determined by reaction with DPPH compare? Is this consistent with the behavior in the body? Why or why not? Berger et al. mention two other stable neutral radicals, TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) and Fremy's salt. In a reversal from the use of stable radicals to measure antioxidant properties, these two molecules have proven to be very versatile oxidation catalysts in organic synthesis, and would make a rich source of research papers for students in undergraduate organic courses.
Free Radicals |
Natural Products
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Biologically Active Exceptions to the Octet Rule Ed Vitz
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Lewis Structures |
Free Radicals |
Vitamins
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Exceptions to the Octet Rule Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Lewis Structures |
Free Radicals |
Molecular Properties / Structure
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Copper, Brass, Bronze
Volume 03, issue 25 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Metallurgy
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Iron and Steel
Volume 03, issue 27 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Metallurgy
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Nickel
Volume 03, issue 28 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Metallurgy
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Vanadium and Its Relatives
Volume 03, issue 30 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Metallurgy
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Ornaments
Volume 04, issue 21 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Metallurgy
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Chemical Leaflets, volume 04, issue 23
Volume 04, issue 23 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Metallurgy
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Copper and Its Alloys
Volume 04, issue 24 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Metallurgy
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Tin and Lead
Volume 04, issue 25 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Metallurgy
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Iron and Its Alloys
Volume 04, issue 26 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Metallurgy
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Nickel and Its Relatives
Volume 04, issue 27 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Metallurgy
|
Chromium and Its Relatives
Volume 04, issue 28 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Metallurgy
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Vanadium and Its Relatives
Volume 04, issue 29 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Metallurgy
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Metallurgy Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Metallurgy
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Refining of Metals Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Metallurgy
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Chromate-Dichromate (GCMP) David M. Whisnant
Chromate/Dichromate: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will study shifts in the equilibrium between chromate and dichromate. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.
Oxidation / Reduction
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Halogens and Halides (GCMP) David M. Whisnant
Halogens and Halides: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will study the oxidation-reduction reactions between the halogens and the halide ions. The halogens and halides will be dissolved in water and hexane. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.
Oxidation / Reduction
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Redox Reactions Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Oxidation / Reduction
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Balancing Redox Equations Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Oxidation / Reduction
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Common Oxidizing Agents Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Oxidation / Reduction
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Redox Couples Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Oxidation / Reduction
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Precious Metals
Volume 03, issue 24 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Geochemistry |
Metallurgy
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Beneficiation Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Metallurgy |
Metals
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A Greener Bleach Stacy Gates
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Oxidation / Reduction |
Green Chemistry
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Corrosion in Astronomy Robert Hetue
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Oxidation / Reduction |
Metals |
Astrochemistry
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Electrolysis Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Electrochemistry |
Oxidation / Reduction
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Common Reducing Agents Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Metals |
Oxidation / Reduction
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Tin and Lead
Volume 03, issue 26 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Metallurgy |
Dyes / Pigments
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Chromium and Its Relatives
Volume 03, issue 29 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Dyes / Pigments |
Metallurgy
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Reduction of Metals Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Industrial Chemistry |
Metallurgy
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Substances Which Are Both Oxidizing and Reducing Agents Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Oxidation / Reduction |
Water / Water Chemistry
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Things We Use
Volume 03, issue 01 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Metallurgy |
Consumer Chemistry |
Industrial Chemistry
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Corrosion Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Electrolytic / Galvanic Cells / Potentials |
Oxidation / Reduction
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Netorials
The Netorials cover selected topics in first-year chemistry including: Chemical Reactions, Stoichiometry, Intermolecular Forces, Acids & Bases, Biomolecules, and Electrochemistry.
Acids / Bases |
Stoichiometry |
Proteins / Peptides |
Enzymes |
Carbohydrates |
Nucleic Acids / DNA / RNA |
Lipids |
Oxidation / Reduction |
Noncovalent Interactions
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General Chemistry Multimedia Problems David M. Whisnant
General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.
Acids / Bases |
Atomic Spectroscopy |
Calorimetry / Thermochemistry |
Isotopes |
Magnetic Properties |
Phases / Phase Transitions / Diagrams |
Surface Science |
Thermodynamics |
Equilibrium |
Oxidation / Reduction
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