Volume Percent (%v/v)

Liquid volumes over a wide range of magnitudes are conveniently measured using common and relatively inexpensive laboratory equipment. The concentration of a solution formed by dissolving a liquid solute in a liquid solvent is therefore often expressed as a volume percentage, %vol or (v/v)%:

$volume\,percentage\,=\frac{volume\,solute}{volume\,solution}\,×\,100$%

Calculations using Volume Percentage

Rubbing alcohol (isopropanol) is usually sold as a 70%vol aqueous solution. If the density of isopropyl alcohol is 0.785 g/mL, how many grams of isopropyl alcohol are present in a 355 mL bottle of rubbing alcohol?

Solution
Per the definition of volume percentage, the isopropanol volume is 70% of the total solution volume. Multiplying the isopropanol volume by its density yields the requested mass:

$$(355\,mL\,solution)(\frac{70\,mL\,isopropyl\,alcohol}{100\,mL\,solution})(\frac{0.785\,g\,isopropyl\,alcohol}{1\,mL\,isopropyl\,alcohol})=\,195\,g\,isopropyl\,alcohol$$