How many moles of Cacl are needed to be dissolved in .500g of H2O to form a 1.5m solution?

Answer 1

First, calcium chloride is CaCl2.
Second, 0.500 g is not very much H2O to be using to prepare any kine of solution. Check your problem and your post.

You want 1.5 m solution. The definition is
m = mols/kg solvent
1.5m=moles/kg. I don't know if that is 0.5 grams or 0.5 kg. You substitute whatever goes there.
Solve for moles, then substitute into the following:
moles = grams/molar mass and calculate grams.