Gibbs free energy defined

The excess energy associated with an interface is formally defined in terms of a surface energy. This may be expressed in terms either of Gibbs, G, or Helmholtz, A, free energies. In order to circumvent difficulties associated with the unavoidably arbitrary position of the surface plane, the surface energy is defined as the surface excess [7,8], i.e the excess (per unit area) of the property concerned consequent upon the presence of the surface. Thus Gibbs surface free energy is defined by... 

Gibbs free energy (G) is probably the most freqnently nsed quantity in thermodynamics it measnres spontaneity of a reaction or energy available to do work in a system. Free energy is a state fnnction because it is defined formally only in terms of the state fnnctions enthalpy and entropy and the state variable temperature. The Gibbs free energy is defined as... 

Application to Macromolecular Interactions. Chun describes how one can analyze the thermodynamics of a particular biological system as well as the thermal transition taking place. Briefly, it is necessary to extrapolate thermodynamic parameters over a broad temperature range. Enthalpy, entropy, and heat capacity terms are evaluated as partial derivatives of the Gibbs free energy function defined by Helmholtz-Kelvin s expression, assuming that the heat capacities integral is a continuous function. 

However, the more important quantity for ordinary laboratory conditions is the Gibbs free energy G, defined as... 

Eq. (12-2) gives us a criterion for spontaneity, but it is restricted to systems that are not in thermal or mechanical contact with the surroundings. A more useful criterion is based on the Gibbs free energy, G, defined by... 

Instead of using volume and temperature as independent variables. however we more often wish to use pressure and temperature. In this case, instead of using t he Helmholtz free energy, it is more convenient to use the Gibbs free energy G. defined bv the equations... 

Gibbs free energy, also known as free energy, provides a way to predict the spontaneity of a reaction using a combination of the enthalpy and entropy of a reaction. Free energy is defined as... 

There is also an interesting relation between AG and the surface free energy, y, defined by Gibbs [cf. Equations 514 and 675 of (6) ]. 

The volume of the solvent, which is transferred through the membrane, is capable of performing work against a pressure, r, denoted the osmotic pressure. If the Gibbs free energy is defined as... 

This criterion of equilibrium is an important one and is frequently used, since most experiments are carried out at constant temperature and pressure. In order to express Eq. (6-12) in a more concise fashion, it is useful to define an extensive function of state, F, the Gibbs free energy. The Gibbs free energy is defined by the relation... 

In defining surface thermodynamic functions, the difficulty over the absence of a unique surface plane is circumvented by defining these functions in terms of surface excess— total minus bulk value of the property concerned [46,47]. Thus the Gibbs surface free energy is defined as... 

Before starting the thermodynamic analysis of electric-chemical field effects it is necessary to recall some relations familiar from processes in the absence of external electric fields. The most general equilibrium condition for processes where the temperature and the pressure are under experimental control is that the characteristic Gibbs free energy is at its minimum. The Gibbs free energy is defined by... 

The molar excess Gibbs free energy is defined as ... 

In this chapter, the fundamental concepts of colloid science have been introduced. The definition of colloidal particles, those with sizes (in all directions) ranging from 1 nm to 10 pm, has been presented, and their relevance in soil science is stated. The importance of surface properties was remarked, introducing several definitions. The specific surface area is the area per unit mass the surface tension (or surface free energy) is defined as the Gibbs free energy per unit area. The surface excess of a given species is the amount (in moles per unit area) which is accumulated... 

The most useful set of variables (for condensed systems) comprises the absolute temperature T, pressure p and number of moles of each spedes i. The corresponding thermodynamic potential is the Gibbs free energy G defined as follows ... 

Let us consider the Gibbs excess free energy as defined by (1.7.1)... 

The rate of crystal growth is dependent on two factors temperature and molecular weight. Temperature affects the growth and formation of crystals due to the Gibbs free energy. Gibbs free energy can be defined as... 

The chemical potential p, of the adsorbate may be defined, following standard practice, in terms of the Gibbs free energy, the Helmholtz energy, or the internal energy (C/,). Adopting the last of these, we may write... 

The first term, AG°, is the change in Gibb s free energy under standard-state conditions defined as a temperature of 298 K, all gases with partial pressures of 1 atm, all solids and liquids pure, and all solutes present with 1 M concentrations. The second term, which includes the reaction quotient, Q, accounts for nonstandard-state pressures or concentrations. Eor reaction 6.1 the reaction quotient is... 

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