AskDefine | Define dissociating

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English

Verb

dissociating
  1. present participle of dissociate

Extensive Definition

Dissociation in chemistry and biochemistry is a general process in which ionic compounds (complexes, molecules, or salts) separate or split into smaller molecules, ions, or radicals, usually in a reversible manner. When a Bronsted-Lowry acid is put in water, a covalent bond between an electronegative atom and a hydrogen atom is broken by heterolytic fission, which gives a proton and a negative ion. Dissociation is the opposite of association and recombination. The process is frequently confused with ionization.

Dissociation constant

For reversible dissociations in a chemical equilibrium
AB \leftrightarrow A + B
the dissociation constant Kd is the ratio of dissociated to undissociated compound
K_d = \frac

Salts

The dissociation of salts by solvation in a solution like water means the separation of the anions and cations. The salt can be recovered by evaporation of the solvent. See also: Solubility equilibrium

Acids

The dissociation of acids in a solution means the split-off of a proton H+, see Acid-base reaction theories. This is an equilibrium process, meaning that dissociation and recombination takes place at the same time. The acid dissociation constant Ka is an indicator of the acid strength: stronger acids have a higher Ka value (and a lower pKa value).

Fragmentation

Fragmentation of a molecule can take place by a process of heterolysis or homolysis

Receptors

Receptors are proteins that bind small ligands. The dissociation constant Kd is used as indicator of the affinity of the ligand to the receptor. The higher the affinity of the ligand for the receptor the lower the Kd value (and the higher the pKd value).
dissociating in Bulgarian: Електролитна дисоциация
dissociating in Czech: Disociace molekul
dissociating in Danish: Dissociation
dissociating in German: Dissoziation (Chemie)
dissociating in Spanish: Disociación
dissociating in French: Dissociation (chimie)
dissociating in Italian: Dissociazione (chimica)
dissociating in Lithuanian: Disociacija
dissociating in Hungarian: Disszociáció
dissociating in Dutch: Dissociatie (scheikunde)
dissociating in Japanese: 解離 (化学)
dissociating in Polish: Dysocjacja elektrolityczna
dissociating in Slovak: Disociácia (chémia)
dissociating in Serbian: Електролитичка дисоцијација
dissociating in Finnish: Dissosiaatio (kemia)
dissociating in Swedish: Dissociation (kemi)
dissociating in Ukrainian: Електролітична дисоціація
dissociating in Chinese: 离解
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