Mass %, Volume % & w/v | Concentration Terms Class 11

Mass %, Volume % & Mass/Volume %

Percentage Concentration Terms | Basic Concepts of Chemistry

1. Mass by Mass Percentage ($\% w/w$)

Also known as weight by weight percentage. It represents the mass of solute present in 100 grams of the solution.

$$\% (w/w) = \frac{\text{Mass of Solute}}{\text{Total Mass of Solution}} \times 100$$

Important: Total Mass of Solution = Mass of Solute + Mass of Solvent.

Temperature Effect: Since mass does not change with temperature, $\% w/w$ is independent of temperature.

Example: 10% w/w glucose means 10g glucose is dissolved in 90g water (Total 100g).

Used for liquid-liquid solutions. It represents the volume of solute present in 100 mL of the solution.

$$\% (v/v) = \frac{\text{Volume of Solute}}{\text{Total Volume of Solution}} \times 100$$

Temperature Effect: Since volume expands/contracts with heat, $\% v/v$ depends on temperature.

Example: 35% v/v Ethylene Glycol (Antifreeze) means 35 mL of glycol is present in 100 mL of solution.

Commonly used in medicine and pharmacy. It represents the mass of solute (in grams) dissolved in 100 mL of the solution.

$$\% (w/v) = \frac{\text{Mass of Solute (g)}}{\text{Volume of Solution (mL)}} \times 100$$

Temperature Effect: Depends on temperature.

Example: 0.9% w/v Saline (NaCl) means 0.9g NaCl is dissolved in 100 mL of solution.

Term	Symbol	Formula Basis	Temp Dependent?
Mass %	$\% w/w$	Mass / Mass	No
Volume %	$\% v/v$	Vol / Vol	Yes
Mass/Vol %	$\% w/v$	Mass / Vol	Yes

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