| Gibbs energy of activation | The Gibbs energy that must be added to that already possessed by a molecule or molecules in order to initiate a reaction. (05 Mar 2000) |
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| gibbs free energy | The total amount of energy which is either used up or released during a chemical reaction. Gibbs free energy (delta G) = (delta H) - t (delta s): where (delta H) is the change in enthalpy, calculated by adding up the amount of energy released or used up to break or form chemical bonds during the reaction, t is the temperature at which the reaction took place, and (delta S) is the change in entropy, or amount of disorder, that occurs in the molecules involved during the reaction. (09 Oct 1997) |
| 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. (05 Mar 2000) |
| gibbs-donnan effect | The observation that charged molecules starting on one side of a semipermeable membrane sometimes will not evenly distribute themselves by diffusion on both sides of the membrane. This effect is probably because there are other charged substances already present which cannot move through the membrane themselves and which are creating an electric field that influences the movement of the incoming charged molecules. (09 Oct 1997) |
| Gibbs-Donnan equilibrium | An equilibrium established between a charged, immobile colloid (such as clay, ion exchange resin or cytoplasm) and a solution of electrolyte. Characteristics: ions of like charge to the colloid tend to be excluded, ions of opposite charge tend to be attracted, the colloid compartment is electrically polarized relative to the solution in the same direction as the colloid charges (a Donnan potential) and the osmotic pressure is higher in the colloid compartment. (18 Nov 1997) |
| Gibbs-Helmholtz equation | An equation expressing the relationship in a galvanic cell between the chemical energy transformed and the maximal electromotive force obtainable. (05 Mar 2000) |
| gibbsite | <chemical> A hydrate of alumina. Origin: Named after George Gibbs. Source: Websters Dictionary (01 Mar 1998) |
| gibbus | Extreme kyphosis, hump, or hunch; a deformity of spine in which there is a sharply angulated segment, the apex of the angle being posterior. Origin: L. A hump (05 Mar 2000) |
| gibe | To cast reproaches and sneering expressions; to rail; to utter taunting, sarcastic words; to flout; to fleer; to scoff. "Fleer and gibe, and laugh and flout." (Swift) Origin: Cf. Prov. F. Giber, equiv. To F. Jouer to play, Icel. Geipa to talk nonsense, E. Jabber. Source: Websters Dictionary (01 Mar 1998) |
| gibel | <zoology> A kind of carp (Cyprinus gibelio); called also Prussian carp. Origin: G. Gibel, giebel. Source: Websters Dictionary (01 Mar 1998) |
| gibfish | The male of the salmon. Source: Websters Dictionary (01 Mar 1998) |
| giblets | The inmeats, or edible viscera (heart, gizzard, liver, etc), of poultry. Origin: OE. Gibelet, OF. Gibelet game: cf. F. Gibelotte stewed rabbit. Cf. Gibbier. Source: Websters Dictionary (01 Mar 1998) |
| Gibney | Virgil P., U.S. Orthopedist, 1847-1927. See: Gibney's fixation bandage, Gibney's boot. (05 Mar 2000) |
| Gibney's boot | Adhesive tape treatment of a sprained ankle or similar condition, applied in a basket-weave fashion under the sole of the foot and around the back of the lower leg. (05 Mar 2000) |
| Gibney's fixation bandage | A herring-bone strapping of the foot and leg for sprain of the ankle. (05 Mar 2000) |