I had to do this experiment for Chemistry and we covered them in zinc dust, the soaked them in heated 20 ml of zinc chlorid, pulled them out (and they were silver in color), and then heated them (and they turned gold in color). The last question on my lab worksheet is, Did the penny change to silver metal and then to gold metal? Explain.I know it didn‘t change to gold metal but I can‘t explain it (because I don‘t know the scientific reason for it not turning into gold metal).If you can help me in anyway, that would be really great.My lab sheet is due tomorrow, so I need an answer quick!Thanks!
When your penny turned gold it was turning into bronze, which is an alloy of the two metals that were present. The silver was a zinc coating you created on the penny from the first step. When you heated it, the zinc and copper combined to create an alloy known as bronze.
I'll give you a hint: The Zinc is reacting with the copper metal, which is changing the chemical composition at the surface of the penny. You are not changing the type of metal of the penny, but rather, altering it's appearance by reacting its surface with something. The same goes for the heating, etc. Look it up. I hope this helps!
It got coated with zinc apparently and then formed a compound or alloy of some sort. It could not have been silver or gold, because they were not present in the reaction and it is not possible to change copper or zinc into gold or silver by ordinary chemical means. You would have to actually change the nucleus of the atoms involved. The common alloy of copper and zinc is called brass, which is gold in color when not tarnished.
