375 g of water dissolved in 125 g of copper sulfate pentahydrate, determine the mass fraction of bivalent

375 g of water dissolved in 125 g of copper sulfate pentahydrate, determine the mass fraction of bivalent copper sulfate in the solution.

Given: m (H2O) = 375 g; m (CuSO4 * 5H2O) = 125 g. It is necessary to find the mass fraction of W (CuSO4) =?
In order to find the mass fraction of pure copper sulfate, you need to subtract the mass of its hydrogenated part (that is, 5H2O)
for this, we consider the mass fraction of 5H2O in the compound:
W (5H2O) = 18 * 5/250 = 0.36
Next, we consider the mass of pure copper sulfate:
m (CuSO4) = 0.36 * 125 = 45g
And we consider the mass fraction of copper sulfate in the entire solution:
W (CuSO4) = (45/375) * 100% = 12%
Answer: the solution contains 12% pure copper sulfate.