Gibbs-Donnan equilibrium

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Don·nan e·qui·lib·ri·um

when a semipermeable membrane or its equivalent (for example, a solid ion exchanger) separates a nondiffusible substance, such as protein, from diffusible substances, the diffusible anions and cations are distributed on the two sides of the membrane so that 1) the products of their concentrations are equal, and 2) the sum of the diffusible and nondiffusible anions on either side of the membrane is equal to the sum of the concentrations of diffusible and nondiffusible cations; the unequal distribution of diffusible ions thus produced creates a potential difference across the membrane (membrane potential).
[Frederick G. Donnan]
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Frederick G., English physical chemist, 1870-1956.
Donnan equilibrium - the equilibrium of small ions between a solution with charged macromolecules, and one without. Synonym(s): Gibbs-Donnan equilibrium
Gibbs-Donnan equilibrium - Synonym(s): Donnan equilibrium


J. Willard, U.S. mathematician and physicist, 1839-1903.
Gibbs energy of activation - energy that must be added to that already possessed by a molecule(s) in order to initiate a reaction.
Gibbs free energy
Gibbs theorem - substances that lower the surface tension of the pure dispersion medium tend to collect in its surface, whereas substances that raise the surface tension tend to remain out of the surface film.
Gibbs-Donnan equilibrium - Synonym(s): Donnan equilibrium
Gibbs-Helmholtz equation - an equation expressing the relationship in a galvanic cell between the chemical energy transformed and the maximal electromotive force obtainable. Synonym(s): Helmholtz-Gibbs theory
Helmholtz-Gibbs theory - Synonym(s): Gibbs-Helmholtz equation
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