Apparatus: small beaker, glass rod, r_rucible tongs, Bunsenburner, tripod, asbestos wire

Chemicals: conc. NaOH, some copper coins, zinc dust

Procedure:

Put into the beaker around 20-30 ml of the concentrated NaOH-solution, one spatula of zinc dust and some clean copper coins. Heat the mixture until boiling.
After 2 minutes remove the coins from the mixture by using the crucible tongs and clean them with water. Observation?

Now hold the coins into the flame of the burner just until the golden colour appears.

Explanation:

In the heat zinc dissolves under basic conditions to form Zn2+ - ions.
They form the silver surface on the coins due to a redox reaction whereby copper and zinc ions are exchanged.(reaction?)
In the flame copper and zinc form an alloy called brass.