Chemistry in Pictures: Dissolving money

Undergraduate Megan Prien dissolved a nickel in nitric acid to measure how much copper it contained as part of an analytical chemistry lab at University of Wisconsin, Whitewater. When Prien added the coin to the acid and heated it, the liquid began to fizz and release nitrogen dioxide gas. The fumes initially were light brown but grew darker as the reaction proceeded. “Of course, all of this took place in a fume hood” for safety, Prien says. The blue-green liquid shown here is dissolved copper. Prien plated the copper onto an inert electrode, which she weighed before and after to determine the mass of the metal. She found that a 1994 nickel contains about 3.65 g of copper.

Submitted by Megan Prien

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CORRECTION: This story was updated on Feb. 22, 2018, to clarify that the coin was dissolved, not melted, in nitric acid.