Mass percent is defined as the mass of solute per what quantity, multiplied by 100?

• A. Mass of solute per solvent times 100
• B. Mass of solute per solution times 100
• C. Moles per liter
• D. Volume per mass times 100

Answer: (B)

Mass percent expresses how much of the total mass of a solution is solute. It is the mass of solute divided by the total mass of the solution (which is solute plus solvent), multiplied by 100. This shows concentration by mass independent of volume. The other ideas don’t fit because mass per solvent uses only the solvent in the denominator, and molarity (moles per liter) or volume-based percent describe different ways to express concentration.

Example: if you have 5 g of solute in 95 g of solvent, the total solution mass is 100 g, so mass percent = (5/100) × 100% = 5%.