Final answer:
To calculate the percent by mass, divide the mass of each component by the mass of the compound and multiply by 100%.
Step-by-step explanation:
To calculate the percent by mass of each component of a solution, you divide the mass of each component by the mass of the compound and multiply by 100%. For example, if you have a 100 g solution composed of 25 g of solute and 75 g of solvent, the percent by mass of the solute would be (25 g / 100 g) * 100% = 25% and the percent by mass of the solvent would be (75 g / 100 g) * 100% = 75%.