From Big Medical Encyclopedia

EBULLIOMETRYYa (Latin of ebullire to boil + Greek metreo to measure, measure; a synonym ebullioscopy) — the physical and chemical method of a research based on definition of increasing boiling point of solution in comparison with temperature of boiling of pure solvent.

AA. along with a kriometriya (see) the pier is used for definition. scales (masses) of solute, osmotic pressure (see), and also extents of dissociation of weak electrolytes (see). In biol. researches E. it is applied to studying physical. - chemical properties biol. liquids.

According to the Raoult's law (see Raul the law), for infinitely diluted solution of non-volatile substance in the absence of electrolytic dissociation (see Dissociation in chemistry) increasing boiling point (At) is proportional to molar concentration (m) of solution: At = Ee-t, where Ee — the ebulliometrichesky constant characteristic of each solvent and not depending by nature solute; Ee for water it is equal 0,526, for benzene 2,57, for camphor 6,02 (these sizes express in degrees Celsius). Pier. the mass (M) of solute, using E., calculate on the equation:

M = Pi - Ee-1000,


where Pi and P2 — the mass of solute and solvent in grams. This equation is fair only for the diluted solutions of nonelectrolytes; if solute dissociates, then enter the so-called coefficient of Vant Hoff (i) showing in how many time into the equation the number of moths of solute as a result of dissociation increases. Bibliography: A course of physical chemistry, under the editorship of Ya. I. Gerasimov, t. 1, M., 1969.

JI. M. Ginodman.