I would type the problem but it's really long. I just need to know what the two different results are for dissolving solids because I completely forgot. I think it has to do with if you can bring them back or not ?
Well every substance has a "Ksp" called the solubility which is the product of the concentrations of the products at equilibrium. Most substances will dissolve then go back to solid and redissolve, and based on different factors like temp, conc. of reactants, etc. they will reach a state of equilibrium, the values for the products at this point are the ksp.
For example
Take the Reaction
aX -> Ca+ + Dx-
[a+]^C[x-]^D = Ksp(solubility product) for compound aX
Does that shed any light on this question? I think this is probably posted in the wrong area.