hold each penny in a Bunsen burner flame (3-4 sec.). Students in first few rows report being able to see the zinc turn grey while in the flame. Wash and dry the "gold" penny. Clean the pennies in ...

Zinc and iron also react with hydrochloric acid. Magnesium, zinc and iron also react with sulfuric acid. The products are a salt (in this case a sulfate) and hydrogen. For example: ...

Tell instructor to heat mixture to boiling before performing the demo in class. Clean several pennies with concentrated HCl until they shine. Newer pennies work best, but those produced after 1983 ...