How many grams of copper sulfate and water do you need to take to get 200 gr. 10% copper sulfate solution.

Given:
m solution (CuSO4) = 200 g
ω (CuSO4) = 10%

To find:
m (CuSO4 * 5H2O) -?
m (H2O) -?

Decision:
1) m (CuSO4) = ω (CuSO4) * m solution (CuSO4) / 100% = 10% * 200/100% = 20 g;
2) n (CuSO4) = m (CuSO4) / M (CuSO4) = 20/160 = 0.125 mol;
3) M (CuSO4) = 160 g / mol;
4) n (CuSO4 * 5H2O) = n (CuSO4) = 0.125 mol;
5) M (CuSO4 * 5H2O) = 250 g / mol;
6) m (CuSO4 * 5H2O) = n (CuSO4 * 5H2O) * M (CuSO4 * 5H2O) = 0.125 * 250 = 31.25 g;
7) m (H2O) = m solution (CuSO4) – m (CuSO4 * 5H2O) = 200 – 31.25 = 168.75 g.

Answer: The mass of CuSO4 * 5H2O is 31.25 g; H2O – 168.75 g.