Question

according to lechateliers principle, would increasing the starting concentration of Ca2+ increase or decrease the amount of Ca(IO3)2 that dissolves???

Answer 1

Ca(IO3)2 (s) <=> Ca{2+} (aq) + 2 IO3{-} (aq)

LeChatelier's principle (general form): Any change in status-quo prompts an opposing reaction in the responding system.

So increasing the starting concentration of calcium cation will oppose its production. That is to decrease the dissolution amount of the solid.

Answer 2

Ca(IO3)2 ==> Ca^2+ + 2IO3^-

The easy way to remember what happens is to remember Le Chatelier's principle. It says that a system is equilibrium will try to undo what we do to it. Therefore, if we increase Ca^2+ (whether starting or not) the reaction will try to remove Ca2+ and that means less of the solid will dissolve.