Question

Curious Carl and his lab partner need 100 ml of a 0.10 M CuSO4 solution for lab. Unfortunately, all they have is 1 liter of a 0.50 M CuSO4 stock solution. Cheryl, his lab partner knows what to do. She begins diluting the stock solution with distilled water. How much 0.50 M stock solution is required to make 100 ml of a 0.10 M solution? A) 5.0 ml B) 10.0 ml C) 20.0 ml D) 50.0 ml

Answer 1

This problem is common especially when preparing solutions from stock solution. To solve this, we make use of the dilution formula: C1V1 = C2V2, where,

C1 and C2 are the concentration of solutions 1 and 2, respectively
V1 and V2 are the volume of solutions 1 and 2, respectively

In this case, the resulting equation to determine the amount of 0.50 M stock solution of CuSO4 needed is:
(0.50 M CuSO4)(Volume of 0.50 M stock solution) = (0.10 M CuSO4) (100 mL)

Thus, the final answer is C. 20 mL of 0.50 M stock solution is required to make 100 ml of a 0.10 M CuSO4 solution.