Percentage of Copper in a Penny Lab Answers

Questions:

1. Why didn't the government change pennies to be entirely zinc if that would be cheaper?

Answer: The government uses copper to coat the zinc because zinc is a highly reactive metal.

2. If all of the zinc did not react, how would your final answer be different?

Answer: If not all the zinc reacted, then the final mass of the penny wold be higher, and there would be a higher percent error.


Possible Errors in the Experiment:

If the zinc is not fully exposed, not all of it reacts, thus turning the solution slightly yellow. If not all zinc reacts. the final mass would be higher. This can be solved by cutting the penny directly in half. If you shaved the edge of the penny, this will not fully expose the zinc and it will also make the mass of the copper smaller.