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dissociation

dissociation, in chemistry, separation of a substance into atoms or ions. Thermal dissociation occurs at high temperatures. For example, hydrogen molecules (H2) dissociate into atoms (H) at very high temperatures; at 5,000°K about 95% of the molecules in a sample of hydrogen are dissociated into atoms. Electrolytic dissociation occurs when an electrolyte is dissolved in a polar solvent. For example, when hydrogen chloride, HCl, is dissolved in water to form hydrochloric acid, most of its molecules dissociate into hydrogen ions (H+) and chloride ions (Cl-). Some pure substances spontaneously dissociate. For example, in pure water some of the molecules dissociate to form hydrogen ions and hydroxyl ions. Dissociation is generally reversible; when the atoms or ions of the dissociated substance are returned to the original conditions, they recombine in the original form of the substance. The dissociation constant is a measure of the extent of dissociation. It is represented by the symbol K. In the simplest case, if a substance AB dissociates into two parts A and B and the concentrations of AB, A, and B are represented by [AB], [A], and [B], then K=[A]×[B]/[AB]. The dissociation constant is measured at equilibrium, and its value is usually affected by changes in temperature.

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"dissociation." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. 14 Dec. 2017 <http://www.encyclopedia.com>.

"dissociation." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (December 14, 2017). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/dissociation

"dissociation." The Columbia Encyclopedia, 6th ed.. . Retrieved December 14, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/dissociation

dissociate

dis·so·ci·ate / diˈsōshēˌāt; -ˈsōsē-/ • v. [tr.] 1. disconnect or separate (used esp. in abstract contexts) : voices should not be dissociated from their social context. ∎  (dissociate oneself from) declare that one is not connected with or a supporter of (someone or something): he took pains to dissociate himself from the religious radicals. ∎  [intr.] become separated or disconnected: the area would dissociate from the country. ∎  (usu. be dissociated) Psychiatry split off (a component of mental activity) to act as an independent part of mental life. 2. (usu. be dissociated) Chem. cause (a molecule) to split into separate smaller atoms, ions, or molecules, esp. reversibly: these compounds are dissociated by solar radiation to yield atoms of chlorine. ∎  [intr.] (of a molecule) undergo this process. DERIVATIVES: dis·so·ci·a·tive / -ˌātiv; -shətiv/ adj.

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"dissociate." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. 14 Dec. 2017 <http://www.encyclopedia.com>.

"dissociate." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. (December 14, 2017). http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/dissociate-0

"dissociate." The Oxford Pocket Dictionary of Current English. . Retrieved December 14, 2017 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/dissociate-0

dissociation

dissociation (dis-soh-si-ay-shŏn) n. (in psychiatry) the process whereby thoughts and ideas can be split off from consciousness and may function independently, allowing conflicting opinions to be held at the same time about the same object. Dissociation may be the main factor in cases of dissociative fugue and multiple personalities (see dissociative disorder).
dissociative (dis-soh-shă-tiv) adj.

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"dissociation." A Dictionary of Nursing. . Encyclopedia.com. 14 Dec. 2017 <http://www.encyclopedia.com>.

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dissociate

dissociate XVII. f. pp. stem of L. dissociāre, f. DIS- 1 + sociāre join together, f. socius companion; see -ATE 3.
So dissociation XVII.

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"dissociate." The Concise Oxford Dictionary of English Etymology. . Encyclopedia.com. 14 Dec. 2017 <http://www.encyclopedia.com>.

"dissociate." The Concise Oxford Dictionary of English Etymology. . Encyclopedia.com. (December 14, 2017). http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/dissociate-1

"dissociate." The Concise Oxford Dictionary of English Etymology. . Retrieved December 14, 2017 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/dissociate-1

dissociate

dissociate •labiate •irradiate, radiate •mediate • ideate • repudiate •palliate, retaliate •affiliate, ciliate, conciliate, humiliate •exfoliate, foliate •nucleate • permeate • delineate •calumniate • expiate •expatriate, repatriate •recreate • inebriate •aureate, excoriate •procreate •appropriate, expropriate, impropriate, misappropriate •infuriate, luxuriate •asphyxiate • nauseate •annunciate, enunciate •instantiate, substantiate, transubstantiate •differentiate, potentiate •expatiate, ingratiate, satiate •appreciate, depreciate •initiate, officiate, propitiate, vitiate •associate, dissociate, negotiate •excruciate • aviate •abbreviate, alleviate, deviate •obviate • exuviate • inchoate •actuate • perpetuate • effectuate •habituate • fluctuate • punctuate •graduate • individuate • menstruate •accentuate, eventuate •evacuate •evaluate, valuate •superannuate • infatuate •attenuate, extenuate •insinuate • situate

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"dissociate." Oxford Dictionary of Rhymes. . Encyclopedia.com. 14 Dec. 2017 <http://www.encyclopedia.com>.

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"dissociate." Oxford Dictionary of Rhymes. . Retrieved December 14, 2017 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/dissociate