Experiment 13: Zinc Sulfate from Copper Sulfate
I have already made instructions for an electroplating version of the silver penny experiment (Experiment 10: Silver Pennies by Electrochemistry), but, as of now, I have not been able to perfect the transition from that to a gold penny. A chemist friend suggested that the zinc was too thick, which seems reasonable. Thus, I needed zinc sulfate to try the more common silver penny experiment in preparation for making a gold penny. To make zinc sulfate, I filled a test tube half-way full with aqueous copper sulfate. Then, I took some strips of zinc I obtained by taking apart a zinc-carbon battery (i.e. like the one from Experiment 4: Carbon Rods) and, after washing them, placed them in the test tube. Truly, mad scientists cannot be more happy when they have an awesome test tube of a mysterious blue liquid. After approximately half an afternoon, I came back and the solution was clear. If you attempt this, you must wait until the solution is clear, or else the copper sulfate will not be completely reacted. The reaction is a single replacement reaction where the zinc replaces the copper in the sulfate, making zinc sulfate and copper metal. The zinc had some weird fuzzy growths of copper, so I filtered the entire solution to obtain some leftover zinc, copper slurry, and a crystal-clear solution of zinc sulfate. Although I said copper multiple times, looking at my real product (a black powder), it seems as if it is not copper. Online, someone said that the reaction produces heat, which would make cupric oxide, a black powder. They also noted that the reaction produces some hydrogen gas, so that would explain the bubbles. Check out the time lapse below and stay tuned for a post on making shiny silver pennies!