Osmolality

Osmolality is the amount of osmotically active substances dissolved in a unit mass of solvent. It is usually expressed in Osm/kg or in fractions of this unit.

Osmolality is equal to the product of molality and the number of particles formed by the dissociation of one molecule.

However, most body fluids are real, i.e., non-ideal solutions where the real osmolality is less than the ideal osmolality. To obtain the value of the real osmolality, you need to know the osmotic coefficient of the solution, by which the value of the ideal osmolality of the solution is multiplied.

The physiological value of plasma osmolality is about 300 mOsm/kg of water.

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related articles

 * Serum osmolality
 * Urine osmolality
 * Osmolarity
 * Osmotic pressure