800 g of a solution with a mass fraction of salt equal to 1% was evaporated to 400 g.

800 g of a solution with a mass fraction of salt equal to 1% was evaporated to 400 g. Determine the mass fraction of salt in the resulting solution and the mass of evaporated water.

Let’s find how much salt was contained in 800 g of a 1% solution:

(1% / 100%) * 800 = 8 g.

In the process of evaporation, only water left the solution, and the salt remained.

The mass of the evaporated water was 800 – 400 = 400 g.

The mass fraction of salt in the resulting solution was:

(8: 400) * 100% = 2%.