The thermodynamic function as defined by the equation: G = H - TS. See free energy.
(G) Gibbs' free energy. A thermodynamic property devised by Josiah Willard Gibbs in 1876 to predict whether a process will occur spontaneously at constant pressure and temperature. Gibbs free energy is defined as G = H - TS where , and are the enthalpy, temperature, and entropy. Changes in G correspond to changes in free energy for processes occuring at constant temperature and pressure; the Gibbs free energy change corresponds to the maximum nonexpansion work that can be obtained under these conditions. The sign of Delta G is negative for all spontaneous processes and zero for processes at equilibrium.
Gibbs free energy () is an important function in chemical thermodynamics, defined by G = H-TS where is the enthalpy, the entropy, and the thermodynamic temperature. Gibbs free energy is the energy liberated or absorbed in a reversible process at constant pressure and constant temperature. Sometimes called Gibbs energy and, in older literature, simply "free energy". Changes in Gibbs free energy, Δ, are useful in indicating the conditions under which a chemical reaction will occur. If Δ is negative the reaction will proceed spontaneously to equilibrium. In equilibrium position Δ
The Gibbs free energy is the Helmholtz free energy plus the product of the system volume and the external pressure. Changes in the Gibbs free energy at a constant pressure thus include work done against external pressure as a system undergoes volumetric changes. This proves convenient for describing equilibria in gases and liquids at a constant pressure (e.g., at one atmosphere), but is of little use in describing machine-phase chemical processes. Changes in the Gibbs free energy caused by a change in the applied pressure (at constant volume) have no direct physical significance. (See also enthalpy.)
a thermodynamic quantity that is the difference between a system's internal energy and the product of its absolute temperature and energy; the portion of energy of a natural system that can be used for work.
chemical processes usually take place at constant pressure and temperature. Under these circumstances, G is the best choice to calculate energy differences of a system. Also, at equilibrium in thermodynamical systems, G is a minimum
The thermodynamic function 3G = 5H - TSS, where is enthalpy, is absolute temperature. and is entropy. Also called free energy, free enthalpy, or Gibbs function.
Chemical reactions can be made to do work (e.g. produce heat). Energy which is, or which can be, available to do useful work is called Gibbs free energy (G). G = H - TS Where H is the enthalpy, S is the entropy, and T is the absolute temperature.
In thermodynamics, the Gibbs free energy is a thermodynamic potential which measures the "useful" work obtainable from an isothermal, isobaric thermodynamic system. Technically, the Gibbs free energy is the maximum amount of non-pV work which can be extracted from a closed system, and this maximum can only be attained in a completely reversible process. When a system evolves from a well-defined initial state to a well-defined final state, the Gibbs free energy ΔG equals the work exchanged by the system with its surroundings, less the work of the pressure forces, during a reversible transformation of the system from the same initial state to the same final state.
