Percent Composition of a Penny
Pennies before 1983 were made of mostly copper. The pennies after 1983 are made with solid zinc and
a thin copper coating. We are going to separate the zinc and copper to find the percent composition.
Materials: penny after 1983, Bunsen burner, tongs, balance
Procedures:
1. Get the mass of the penny.
2. Heat penny with the Bunsen burner over the beaker until zinc falls into beaker. (Refer to drawing).
3. Remove copper envelop from the tongs and douse the tongs ONLY into cool water.
4. Let the copper and zinc cool. Then get the mass of each.
5. Calculate the percent composition of each.
Year on your Penny: _________________
Percent composition:
% Composition of Cu:
% Composition of Zn:
Conclusion:
1. Go to: https://www.usmint.gov/coins/coin-medal-programs/circulating-coins/penny
What is the actual percent composition of a penny?
2. Why did the percent composition of penny change after 1983?