Question

If you put copper coated penny 1983or newer, in vinegar, it turns blackish green. If you rub the copper off half the penny first and expose the zinc, put the penny in vinegar, will the results change?
Thank you.

Answer 1

I don't think so. The black/green color is due to a little Cu that goes into solution. Rubbing HALF the Cu off and exposing the half Zn and half Cu surface still leaves some of the Cu to react.