How many grams of CaCl2 are needed to prepare 25.0 mL of .500 M solution?

and

What volume of 12.00 M HCL is needed to prepare 150.0 mL of .500 M HCL?

1 answer

mols you need = M x L = ?
mols = g/molar mass. You know mols and molar mass, solve for grams.

2.

mL1 x M1 = mL2 x M2
mL1 x 12 = etc.