This activity includes two versions of the lab and teacher instructions for making the solution and setting it up.
Students will coat a copper penny with zinc and then alloy the zinc to the copper to form brass. They will show you a copper penny, a "silver" penny, and a "gold" penny. Students love this lab. You can use it to illustrate physical changes or to reinforce stoichiometry and moles.
There are two versions. One is for pre-ap or honors level chemistry and requires balances that go to 3 decimal places. The second version is appropriate for on-level chemistry or early in the school year. The pre-ap level has students determine the number of atoms of zinc that are deposited on the penny.
You'll love this for the oohs and ahhs you get and how students who don't have your class come to see what your students have done. It's also fun to get a brass coated penny in your change later on and know that it came from your classroom.
Keywords: physical, chemical, stoichiometry, moles, atoms, Avogadro's number, experiment, chemistry, alloy, mass, balance, atomic weight.