Which quantity is needed on top of a solution's volume and mass percentage to find the solute mass?
- The molar mass of the solute
- The density of the solution
- The molarity of the solution
- The mass of the solvent alone
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Correct answer: B. The density of the solution
1. Mass percentage relates the solute mass to the mass of the whole solution.
2. A volume on its own cannot be fed into that relation.
3. The density converts the solution's volume into the solution's mass.
4. The mass percentage is then applied to that mass to give the solute mass.
5. Molar mass is only needed if the answer is wanted in moles rather than grams.
_Source: OpenStax Chemistry (CC BY 4.0), Ch 3 "Composition of Substances and Solutions", section 3.4 Other Units for Solution Concentrations_