From 250 g of 10% sodium sulfate solution, 50 grams of water was evaporated. What is the mass fraction

From 250 g of 10% sodium sulfate solution, 50 grams of water was evaporated. What is the mass fraction of salt in the resulting solution?

1. Calculate the mass of sodium sulfate:

m (Na2SO4) = w (Na2SO4) * mout (solution) = 0.1 * 250 = 25 g;

2. find the mass of the solution obtained by evaporation:

mpol (solution) = mout (solution) – mout (H2O) = 250 – 50 = 200 g;

3. Determine the mass fraction of salt in the resulting solution:

wpol (Na2SO4) = m (Na2SO4): mpol (solution) = 25: 200 = 0.125 or 12.5%.

Answer: 12.5%.