Determine the mass of sodium chloride required to prepare 600 g of a 15% salt solution.

Mass fraction is the ratio of the mass of the solute to the total mass of the solution. It is expressed as a percentage of the total mass of the solution: w = (m / M) * 100, where w is the mass fraction (%), m is the mass of the solute (g), M is the total mass of the solution (g).

In our case, we have a solution with a total mass of 600 g. Mass fraction of salt = 15%. We calculate the mass of water required to prepare the solution: 100 -15 = 75 g of water in 100 g of the solution.

100 g of solution – 75 g of water

In 600 g of solution – x g of water; x = (600 * 75) / 100 = 450 g of water.

Knowing the mass of water for the solution, and the mass of the solution, we calculate the mass of salt: 600 – 450 = 150 g.