Editing Molality (section)

== Usage considerations ==
=== Advantages ===
The primary advantage of using molality as a measure of concentration is that molality only depends on the masses of solute and solvent, which are unaffected by variations in temperature and pressure. In contrast, solutions prepared volumetrically (e.g. [[molar concentration]] or [[mass concentration (chemistry)|mass concentration]]) are likely to change as temperature and pressure change. In many applications, this is a significant advantage because the mass, or the amount, of a substance is often more important than its volume (e.g. in a [[limiting reagent]] problem).

Another advantage of molality is the fact that the molality of one solute in a solution is independent of the presence or absence of other solutes.

=== Problem areas ===
Unlike all the other compositional properties listed in "Relation" section (below), molality ''depends'' on the choice of the substance to be called “solvent” in an arbitrary mixture. If there is only one pure liquid substance in a mixture, the choice is clear, but not all solutions are this clear-cut: in an alcohol–water solution, either one could be called the solvent; in an alloy, or [[solid solution]], there is no clear choice and all constituents may be treated alike. In such situations, mass or mole fraction is the preferred compositional specification.