osmotic /oz mot"ik, os-/, adj.osmotically, adv.
/oz moh"sis, os-/, n.
1. Physical Chem., Cell Biol.
a. the tendency of a fluid, usually water, to pass through a semipermeable membrane into a solution where the solvent concentration is higher, thus equalizing the concentrations of materials on either side of the membrane.
b. the diffusion of fluids through membranes or porous partitions. Cf. endosmosis, exosmosis.
2. a subtle or gradual absorption or mingling: He never studies but seems to learn by osmosis.
[1865-70; Latinized form of now obs. osmose osmosis, extracted from endosmose endosmosis, exosmose exosmosis < F, equiv. to end- END-, ex- EX-2 + Gk osm(ós) push, thrust + F -ose -OSIS]

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Spontaneous passage or diffusion of water or other solvent through a semipermeable membrane.

If a solution is separated from a pure solvent by a membrane that is permeable to the solvent but not to the solute, the solution will tend to become more dilute by absorbing solvent through the membrane. The pressure caused by the migration of solvent through the membrane is called osmotic pressure.

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▪ chemical process
 the spontaneous passage or diffusion of water or other solvents through a semipermeable membrane (one that blocks the passage of dissolved substances—i.e., solutes). The process, important in biology, was first thoroughly studied in 1877 by a German plant physiologist, Wilhelm Pfeffer. Earlier workers had made less accurate studies of leaky membranes (e.g., animal bladders) and the passage through them in opposite directions of water and escaping substances. The general term osmose (now osmosis) was introduced in 1854 by a British chemist, Thomas Graham (Graham, Thomas).

      If a solution is separated from the pure solvent by a membrane that is permeable to the solvent but not the solute, the solution will tend to become more dilute by absorbing solvent through the membrane. This process can be stopped by increasing the pressure on the solution by a specific amount, called the osmotic pressure. The Dutch-born chemist Jacobus Henricus van't Hoff (Hoff, Jacobus Henricus van 't) showed in 1886 that, if the solute is so dilute that its partial vapour pressure above the solution obeys Henry's law (i.e., is proportional to its concentration in the solution), then osmotic pressure varies with concentration and temperature approximately as it would if the solute were a gas occupying the same volume. This relation led to equations for determining molecular weights of solutes in dilute solutions through effects on the freezing point, boiling point, or vapour pressure of the solvent.

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Universalium. 2010.

Look at other dictionaries:

  • osmosis — ósmosis ósmosis f. fisiol. Fenómeno por el que un líquido pasa a través de una membrana semipermeable cuando ambos medios tienen una concentración de solutos diferentes. Medical Dictionary. 2011. osmosis …   Diccionario médico

  • osmosis — ósmosis u osmosis ‘Intercambio de sustancias líquidas a través de una membrana semipermeable’. Aunque también se usa la forma llana osmosis, en la mayor parte del mundo hispánico se prefiere la forma esdrújula ósmosis. Lo mismo cabe decir de sus… …   Diccionario panhispánico de dudas

  • osmosis — ósmosis o osmosis (plural ósmosis) sustantivo femenino 1. Área: química Fenómeno de difusión entre dos soluciones a través de un tabique o membrana semipermeable que las separa, de ma nera que solamente algunos componentes pasan de una solución a …   Diccionario Salamanca de la Lengua Española

  • osmosis — os*mo sis ([o^]z*m[=o] s[i^]s), n. [NL., fr. Gr. wsmo s, equiv. to w^sis impulse, fr. wqei^n to push.] (Chemical Physics) (a) The tendency in fluids to mix, or become equably diffused, when in contact. It was first observed between fluids of… …   The Collaborative International Dictionary of English

  • osmosis — [äs mō′sis, äzmō′sis] n. [ModL, ult. < Gr ōsmos, impulse < ōthein, to push < IE base * wedh , to push, strike > Sans vádhar , deadly weapon] 1. the tendency of a solvent to pass through a semipermeable membrane, as the wall of a… …   English World dictionary

  • osmosis — osmosis. См. осмос. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • osmosis — noun absorption, assimilation, diffusion, digestion, engulfment, infiltration, ingress, interpenetration, introgression, passage, penetration, permeation, saturation, seepage, transmission Burton s Legal Thesaurus. William C. Burton. 2006 …   Law dictionary

  • osmosis — 1867, originally endosmose (1830s) inward passage of a fluid through a porous septum, from Fr. endo inward + Gk. osmos a thrusting, a pushing, from othein to push, to thrust, from PIE *wedhe to push, strike (Cf. Skt. vadhati pushes, strikes,… …   Etymology dictionary

  • ósmosis — (Del gr. ὠσμός, acción de empujar, impulso, y sis). 1. f. Fís. Paso de disolvente pero no de soluto entre dos disoluciones de distinta concentración separadas por una membrana semipermeable. 2. Mutua influencia entre dos personas o grupos de… …   Diccionario de la lengua española

  • osmosis — ► NOUN 1) Biology & Chemistry a process by which molecules of a solvent pass through a semipermeable membrane from a less concentrated solution into a more concentrated one. 2) the gradual assimilation of ideas. DERIVATIVES osmotic adjective.… …   English terms dictionary

  • Ósmosis — Fenómeno de la ósmosis. La ósmosis es un fenómeno físico relacionado con el comportamiento de un sólido como soluto de una solución ante una membrana semipermeable para el solvente pero no para los solutos. Tal comportamiento entraña una difusión …   Wikipedia Español

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