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  Home > JCE Print > Journal of Chemical Education > Issues > 2001  > April  >
In the Classroom
Applications and Analogies
The Household Chemistry of Cleaning Pennies
Laurence D. Rosenhein
Department of Chemistry, Indiana State Universiy, Terre Haute, IN 47809

Cover
April 2001
Vol. 78 No. 4
p. 513

Abstract
Although it is well known that solutions of vinegar and table salt are effective in removing tarnish from pennies, chemical explanations of this behavior are not included in sources of this "household chemistry" and erroneous explanations have crept into popular literature on this subject. This article provides some relevant empirical information on the system, such as the fact that chloride ion (as opposed to any ionic compound) seems to be necessary for the effect, and presents a simplified treatment of equilibria that occur in the solutions. Equilibrium calculations indicate that formation of the copper(I) complex ion CuCl2- is favored, which may explain the role of the sodium chloride. The presence of copper(I) in the resulting solutions can be demonstrated colorimetrically with the reagent bicinchoninic acid.
More Information
*  Citation
Rosenhein, Laurence D. J. Chem. Educ. 2001 78 513.
*  Keywords
Consumer Chemistry; Coordination Chemistry; Copper; General Chemistry
*  History
Created:
Last Updated:
March 2, 2001
April 14, 2005
  Home > JCE Print > Journal of Chemical Education > Issues > 2001 > April > Page 513



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