Question

Calculate the mass of a solute in 300 ml of a solution, if the solution is 75% water? The density of the solution is 1.8g/ml.

Answer 1

As the density of the solution is 1.8 g/ml and the volume is 300 ml, the mass of the solution is:

m(solution) = density(solution) × volume(solution) = 1.8 g/ml × 300 ml = 540 g

If the solution is 75% water, than 25% of the solution is the mass of a solute. From here:

m(solute) = 540 g × 25% / 100% = 135 g

Answer: 135 g