The purpose of this lab was to have students retrieve solid copper from the
copper oxide they formed in a previous lab. This lab reviewed
oxidation-reduction reactions and reactivity series. There were 2 steps to
this process. The first involved separating the copper oxide from the
copper that didn't react. This was done by adding 1 M HCl to the
compound. The solid copper did not react while the copper oxide
formed copper (II) chloride according the equation below:
CuO(s) + 2HCl(l) --> CuCl2(aq) + H2O(l)
The amount of copper that didn't react was taken into account during the calculation for recovery. Zinc pieces were added to the copper (II) chloride solution in order to get the copper out on the zinc according to the equation below:
CuCl2(aq) +Zn(s) --> ZnCl2(aq) + Cu(s)
After drying and weighing, students compared the amount of copper recovered to the amount they started with. Percent recovered in 2006 were 133%, 96%, 96%, 77%, 72%, 55%, 50%, and one group had no report.
Percent recovered in 2007 were 130%, 125%, 110%, 103%, 88%, 80%, 80%, and 52%