In 5 l of water, 500 g of copper sulfate was dissolved. Calculate the mass fraction of copper sulfate (2) in the resulting solution.

1. Find the mass of water:

m (H2O) = V (H2O) * ρ (H2O) = 5000 * 1 = 5000 g.

2. Determine the mass of the solution:

m (solution) = m (H2O) + m (CuSO4 * 5H2O) = 5000 + 500 = 5500 g.

3. Let’s calculate the chemical amount of copper sulfate:

n (CuSO4 * 5H2O) = m (CuSO4 * 5H2O): M (CuSO4 * 5H2O);

M (CuSO4 * 5H2O) = 64 + 32 + 4 * 16 + 5 * 18 = 250 g / mol;

n (CuSO4 * 5H2O) = 500: 250 = 2 mol.

4. The amount of copper sulfate is the same as the amount of copper sulfate:

n (CuSO4) = n (CuSO4 * 5H2O) = 2 mol.

5. Set the mass of sulfate:

m (CuSO4) = n (CuSO4) * M (CuSO4);

M (CuSO4) = 64 + 32 + 4 * 16 = 160 g / mol;

m (CuSO4) = 2 * 160 = 320 g.

6. Let’s calculate the mass fraction of salt:

w (CuSO4) = m (CuSO4): m (solution) = 320: 5500 = 0.0582 or 5.82%.

Answer: 5.82%.