Decay Chemicals

[Frank_Stein]

I'm not huge into chemistry, but how many chemicals decay into other chemicals on their own or when mixed with something else? A lot of stuff that you mix seems to happen instantaneous.

The only thing like this I know off the top of my head is ice melting into water because of heat.

But it would be interesting if you could, say, expose metals to acids that generated electricity from the acid decaying the metal.