Comparison of the Concentration Scales

The molar concentration scale is most appropriate in volumetric experiments using pipets, volumetric flasks, and burets. A disadvantage of this scale is that molar concentrations are temperature-dependent since solution density depends (usually weakly) on temperature.

Concentrations expressed as molality or mole fractions are temperature-independent and are most useful when a physical measurement is related to theory over a range of temperature, e.g., in freezing point depression or boiling point elevation measurements. Since the density of water is close to 1 g/cm³, molal and molar concentrations are nearly equal numerically for dilute aqueous solutions (<0.1 M).