/di soh'see ay"sheuhn, -shee ay"-/, n.
1. an act or instance of dissociating.
2. the state of being dissociated; disjunction; separation: the dissociation of church and state.
3. Physical Chem.
a. the reversible resolution or decomposition of a complex substance into simpler constituents caused by variation in physical conditions, as when water gradually decomposes into hydrogen and oxygen under great heat in such a way that when the temperature is lowered the liberated elements recombine.
4. Psychiatry. the splitting off of a group of mental processes from the main body of consciousness, as in amnesia or certain forms of hysteria.
[1605-15; DIS-1 + (AS)SOCIATION, modeled on L dissociatio separation]

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Breaking of a chemical compound into simpler constituents as a result of added energy, as in the case of gaseous molecules dissociated by heating; also, the effect of a solvent on a dissolved polar compound (electrolyte), as in the case of an inorganic salt, such as sodium chloride, dissolved in water.

All electrolytes dissociate into ions to a greater or lesser extent in polar solvents (in which the molecules are electric dipoles). The degree of dissociation can be used to determine the equilibrium constant. Dissociation is used to explain electrical conductivity and many other properties of electrolytic solutions.

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      in chemistry, the breaking up of a compound into simpler constituents that are usually capable of recombining under other conditions. In electrolytic, or ionic, dissociation, the addition of a solvent or of energy in the form of heat causes molecules or crystals of the substance to break up into ions (electrically charged particles). Most dissociating substances produce ions by chemical combination with the solvent. The idea of ionic dissociation is used to explain electrical conductivity and many other properties of electrolytic solutions.

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Universalium. 2010.

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  • dissociation — (di sso si a sion) s. f. Action de dissocier. La dissociation des éléments d un corps. HISTORIQUE    XVIe s. •   Il a rompu, par le passé, les autres traictés qui ont esté faits de me marier ; dont, entre autres, y en eut un si proche, que la… …   Dictionnaire de la Langue Française d'Émile Littré

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