what causes the copper and zinc to desolve, and cause the change of color?
The following reactions are occuring copper/zinc(s) + nitric acid(aq) ----------> copper/zinc nitrate(aq) + nitrogen oxides(g) + water The metals dissolve because soluble nitrate salts are formed. With copper the colour changes because copper nitrate is blue. Zinc nitrate is white so the solution is colourless. If nitrogen DIoxide is produced it will be seen as a yellow-brown gas. NB This is not the usual reaction of a dilute acid with a metal forming the salt and hydrogen gas and copper does not react with dilute sulphuric and hydrochloric. Nitric acid is an oxidising agent and reacts in this different way with most metals.
Nitric acid is NOT a toy! It reacts with many things, including skin. Nitric acid burns on the skin are among the very slowest to heal. Nitric is a strong acid and a strong oxidizing agent (often producing a brown, chocking gas). I would ask a local college lab or rescue squad if they would take it before someone gets seriously hurt.
