How Much Water must be added to 400mL of a 1.5 mol/L CaCl2 Solution? HELP! fast 10 points

How Much Water must be added to 400mL of a 1.5 mol/L CaCl2 Solution to make the concentration of the resulting solution 0.5 mol/L

EXPLAIN
FAST 10 POINTS

First we find the total amount of CaCl2. We can reasonably find this by multiplying the current volume of he solution by the concentration of the solution using the same units (Litres).
400mL of 1.5 mol/L solution equals 0.6 mol of CaCl2 obtained by multiplying 1.5 mol/L by 0.4L

Then we find how much water will make that reach the desired concentration. If we know we have 0.6 mol of CaCl2 and want it to be at a concentration of 0.5 mol/L then we can divide 0.6 mol by 0.5 mol/L to find the total volume of the final solution.
0.6 mol/(0.5 mol/L) = 1.2L

Then we subract the original volume of the solution from this total volume to see how much water must be added.
1.2L - 0.4L = 800mL