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  Home > JCE Print > Journal of Chemical Education > Issues > 2005  > August  >
Chemistry for Everyone
JCE Featured Molecules
The Chemistry of Coffee
William F. Coleman
Chemistry Department, Wellesley College, Wellesley, MA 02481


Cover
August 2005
Vol. 82 No. 8
p. 1167

Full Text
The paper by Marino Petracco provides a hearty blend of molecules for this month. The author deals with coffee at a number of different levels ranging from the economic and social to the still perplexing questions of flavor and aroma. The associated molecules demonstrate a range of structural features that students will benefit from examining in three dimensions.

Students encountering chemistry for the first time are often dismayed and confused by the range of shorthand representations that we use to convey structural information. Nicotinic acid, for example, is drawn, in the paper and in essentially all other print sources, as a regular hexagon. Students should rightly ask how accurate that representation is, and should be encouraged to use the structure file to measure the relative bond lengths to see the deviation of the actual structure from one with six equal-length sides.

The paper also serves as a rich source of student projects in high school and introductory college courses. Students might be asked to pick one of the aroma producing molecules, find other foods containing that molecule, and look for possible trends.

In addition to the static image, two fully manipulable versions (Jmol, MDLChime) of these molecules appear below. (The Jmol versions may take a few extra seconds to load, based on the speed of your Internet connection.)

These and other molecules are avialable Only@JCE Online.

Image of molecule.

Figure 1. chlorogenic acid

Image of molecule.

Figure 2. trigonelline

Image of molecule.

Figure 3. nicotinic acid

Image of molecule.

Figure 4. 2,4,6-trichloroanisole

More Information
*  Citation
Coleman, William F. J. Chem. Educ. 2005 82 1167.
*  Keywords
Computer-Based Learning; Internet / Web-Based Learning; Molecular Modeling; Molecular Properties / Structure
*  History
Created:
Last Updated:
July 5, 2005
July 8, 2005
  Home > JCE Print > Journal of Chemical Education > Issues > 2005  > August


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