If 31.8 grams of LiCl are dissolved in 225 grams of water, what is the concentration of the solution in percent by mass?

Percent by can be calculated by dividing the amount of solute by the total grams of the solution to be made so the sum of water and the amount solute. We calculate as follows:

% by mass = 31.8 g LiCl / 225 g water + 31.8 g LiCl x 100%

% by mass = 12.38%