energy

The exertion of power; the capacity to do work, taking the forms of kinetic e., potential e., chemical e., electrical e., etc. SYN: dynamic force. [G. energeia, fr. en, in, + ergon, work]

- e. of activation (E_a) e. that must be added to that already possessed by a molecule or molecules in order to initiate a reaction; usually expressed in the Arrhenius equation relating a rate constant to absolute temperature.

- binding e. e. that would be released if a particular atomic nucleus were formed through the combination of individual protons and neutrons. SYN: fusion e..

- chemical e. e. liberated or absorbed by a chemical reaction, e.g., oxidation of carbon, or absorbed in the formation of a chemical compound.

- free e. (F) a thermodynamic function symbolized as F, or G (Gibbs free e.), = H − TS, where H is the enthalpy of a system, T the absolute temperature, and S the entropy; chemical reactions proceed spontaneously in the direction that involves a net decrease in the free e. of the system ( i.e., ΔG < 0).

- fusion e. SYN: binding e..

- Gibbs e. of activation the Gibbs e. that must be added to that already possessed by a molecule or molecules in order to initiate a reaction.

- Gibbs free e. (G) free e..

- Helmholtz e. (A) e. equivalent to the internal e. minus the entropy contribution (TS).

- internal e. (U) e. of a system measured by the heat absorbed from the system's surroundings and the amount of work done on the system by its surroundings.

- kinetic e. (K) the e. of motion.

- latent e. SYN: potential e..

- nuclear e. e. given off in the course of a nuclear reaction or stored in the formation of an atomic nucleus.

- nutritional e. SYN: trophodynamics.

- e. of position SYN: potential e..

- potential e. the e., existing in a body by virtue of its position or state of existence, which is not being exerted at the time. SYN: e. of position, latent e..

- psychic e. in psychoanalysis, a hypothetical mental force, analogous to the physical concept of e., which enables and vitalizes an individual's psychological activity. SEE ALSO: libido. SYN: psychic force.

- radiant e. e. contained in light rays or any other form of radiation.

- solar e. e. derived from sunlight.

- total e. the sum of kinetic and potential energies.

* * *

en·er·gy 'en-ər-jē n, pl -gies

1) the force driving and sustaining mental activity <in psychoanalytic theory the source of psychic \energy is the id>

2) the capacity for doing work

* * *

en·er·gy (enґər-je) [Gr. energeia] the capacity to operate or work; the capacity to produce motion, to overcome resistance, and to effect physical changes. Symbol E.