Evaporated 500 g of a 30% solution of potassium chloride. The mass of the resulting solution is 440g

Evaporated 500 g of a 30% solution of potassium chloride. The mass of the resulting solution is 440g. What is the mass fraction of potassium chloride in the resulting solution?

Given:
m p-pa1 (KCl) = 500 g
ω1 (KCl) = 30%
m p-pa2 (KCl) = 440 g

To find:
ω2 (KCl) -?

Decision:
1) find the mass of dry matter KCl in the original solution:
m (KCl) = ω1 (KCl) * m p-pa1 (KCl) / 100% = 30% * 500/100% = 150 g

2) the mass of the initial solution during evaporation decreased due to water; the mass of dissolved KCl is the same

3) find the mass fraction in the resulting solution:
ω2 (KCl) = m (KCl) * 100% / m p-pa2 (KCl) = 150 * 100% / 440 = 34.1%

Answer: the mass fraction of potassium chloride in the resulting solution is 34.1%.