Concentration of Solutions
Percent by Volume
Percent by volume, or % v/v, refers to the number of milliliters of solute dissolved in 100 mL solution.
\[
\begin{aligned}
\%\, \text{volume/volume}
&=
\frac{
\text{volume of solute}
}{
\text{volume of solution}
}
\times 100
\end{aligned}
\]
The alcohol in an alcoholic beverage is sometimes expressed in percent by volume or in proof number. The proof number is equal to twice the percent by volume of ethyl alcohol in the beverage. For example, when the label on a bottle of whisky reads 86 proof, this means that the whisky contains 43% ethyl alcohol (C2H5OH). Lambanog, or a Philippine wine made from coconut, is 90 proof, so its alcohol content by volume is 45%.
