chemistry Molarity
posted by Kevin .
You have 353 mL of a 1.25 M potassium Chloride solution, but you need to make a 0.50 M potassium Chloride solution. How many milliliters of water must you add to the original 1.25 M solution to make the 0.50 M potassium Chloride solution

mL x M = mL x M
Substitute and solve for mL.
353 x 1.25 = mL x 0.5
Solve for mL and this will be the FINAL VOLUME. To find how much water must be added requires
a. That we assume the volumes are additive.
b. Then final volume in mL  353 mL = mL to be added. 
529.5