<Dl> <Dd> φ i = V i V . (\ displaystyle \ phi _ (i) = (\ frac (V_ (i)) (V)).) </Dd> </Dl> <Dd> φ i = V i V . (\ displaystyle \ phi _ (i) = (\ frac (V_ (i)) (V)).) </Dd> <P> Being dimensionless, it is expressed as a number, e.g., 0.18 or 18%; its unit is 1 . </P> <P> Several other quantities can be used to describe the composition of a mixture . Note that these should not be called concentrations . </P>

Measurements of the concentration of a drug in an aqueous solution could be in what units