What is It From Part 1 of the activity, you were able to express concentration using percent by volume. Another way to express concentration is through: 1. percent by mass – it is defined as the amount of solute in each ma of solvents. It is expressed as grams of solute per 100 grams of soluti (% m/m). Eq.1: percent by mass = mass of solute x 100 mass of solution or mass of solute Eq.2: percent by mass = X 100 mass of solute + mass of solvent​