molality

The term molality is also used for the composition of solutions (see chapter 6).

And m is the molality of the solution.

The composition of a solution can be expressed in various ways including molality and mole fraction.

For binary mixtures, the conversion to molality is given by:

The osmotic coefficient based on molality b is defined by:

The deviations tend to become larger with increasing molality and temperature, but with some exceptions.

When we are investigating temperature and concentration effects, we generally tend to use molality instead, as this is volume independent.

(The molality scale is preferred in thermodynamics because molal concentrations are independent of temperature).

In thermodynamics, the cryoscopic constant, K, allows one to relate molality to freezing point depression.

In this case, there is a more direct equation: we use it to derive the molality of HF:

This problem is usually resolved by introducing temperature correction coefficient, or by using a temperature-independent measure of concentration such as molality.

The SI unit for molality is mol/kg.

Osmolality is a variation of molality that only takes into account solutes that contribute to a solution's osmotic pressure.

Molality can be expressed as the number of moles of solute in one kilogram of solvent.

The molality of the solution is moles of solute (alcohol) per kilogram of solvent.

To avoid ambiguity, the terms "osmolal" and "osmolar" can be used when the units of molality or molarity are consistent throughout the calculation.

The depression in freezing point when a solute is added to a solvent is related to the molality m of the solute.

Solubility may be stated in units of concentration, molality, mole fraction, mole ratio, and other units.

For the general n-solute solution, the mass concentration of the i-th solute, ρ, is related to its molality, b, as follows:

In other animals, such as the spring peeper frog (Pseudacris crucifer), the molality is increased temporarily as a reaction to cold temperatures.

Standard state molality is 1 mol kg, while standard state amount concentration is 1 mol dm.

Actually, it is not easy to purchase 100 % isopropyl alcohol because what's available in the drugstore contains water that must be factored into the calculation of solution molality.

From this you can figure out why electrolytes - on a per mole basis, or of the same molality - can cause higher changes in boiling or freezing points.

When the amount concentration is expressed as a molality, the proportionality constant is known as the ebullioscopic constant ('K') and is characteristic for each solvent.

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.