4 g of Glauber’s salt Na2SO4-IOH was added to 20 g of sodium sulfate solution

4 g of Glauber’s salt Na2SO4-IOH was added to 20 g of sodium sulfate solution with a mass fraction of 20% salt. Calculate the mass fraction of sodium sulfate in the solution.

Given: m1 (solution) = 20.0 g
Omega (1) = 20%
m (Na2SO4 * 10H2O) = 4.0 g
Decision:
m1 (Na2SO4) = (m1 (solution) * Omega1) / 100% = (20 * 20) / 100 = 4 g
m2 (Na2SO4) = m (Na2SO4 * 10H2O) * M (Na2SO4) / M (Na2SO4 * 10H2O) = 4 * 242/322 = 3 g
m (Na2SO4) = m1 (Na2SO4) + m2 (Na2SO4) = 4 + 3 = 7 g
m2 (p-pa) = m1 (solution) + m (Na2SO4 * 10H2O) = 20 + 4 = 24 g
ω2 = (m (Na2SO4) / m2 (p-pa)) * 100% = (7/24) * 100 = 29.2%
Answer: 29%