Gibbs free energy change

Having calculated the standai d values AyW and S" foi the participants in a chemical reaction, the obvious next step is to calculate the standard Gibbs free energy change of reaction A G and the equilibrium constant from... 

The temperature is expressed ia degrees Celsius. The empirical equation for the Gibbs free energy change was found to be linear with temperature for AG° ia kJ/mol, Tia Kelvin. 

A solution is a single-phase mixture of more than one compound, and the driving force for its spontaneous formation from the pure compounds at constant T and p is the negative Gibbs free energy change of the mixing process, —AG, as... 

The Gibbs free energy change of a system will depend not only on temperature and pressure but upon the chemical potentials of the species involved, and this statement may be expressed in the form of the partial differential... 

The enthalpy and Gibbs free energy change can be calculated from the functions involving H°m m by ... 

Figure 7.1 Entropy, enthalpy, and Gibbs free energy changes at T= 298.15 K for forming one mole of an ideal mixture from the components,...

The electromotive force of a cell can be related to the Gibbs free energy change for the cell reaction by combining equations (9.5), (9.90), and (3.96). We recall that... 

Impact on Biology Gibbs Free Energy Changes in Biological Systems... 

IMPACT ON BIOLOGY GIBBS FREE ENERGY CHANGES IN BIOI OCICA1 SYSTEMS... 

The standard Gibbs free energy change per mole accompanying vaporization (the conversion of a substance from the liquid state into the vapor state), standard hydrogen electrode (SHE) A hydrogen... 

It is known that thermodynamic and structural studies are mutually complimentary and both are necessary for a complete elucidation of the molecular details of any binding process for the delineation of the molecular interaction involved at the interaction site. The Gibbs free energy change (AG) may be determined from the binding constant from the relation ... 

Solid ammonium nitrate is an orderly, crystalline substance, a state considerably less random than a solution of ions in water. In this case, the positive entropy change outweighs the enthalpy change. That is TAS > AH. The Gibbs free energy change is negative, so the process will proceed spontaneously. 

And the Gibbs free energy change of activation is given by the Eyring equation ... 

These equations are equivalent to a requirement that the Gibbs free energy change for each reaction (AG) be zero at equilibrium. 

Once the standard states for the various species have been established, one can proceed to calculate a number of standard energy changes for processes involving a change from reactants, all in their respective standard states, to products, all in their respective standard states. For example, the Gibbs free energy change for this process is... 

In order to have a consistent basis for comparing different reactions and to permit the tabulation of thermochemical data for various reaction systems, it is convenient to define enthalpy and Gibbs free energy changes for standard reaction conditions. These conditions involve the use of stoichiometric amounts of the various reactants (each in its standard state at some temperature T). The reaction proceeds by some unspecified path to end up with complete conversion of reactants to the various products (each in its standard state at the same temperature T). 

The enthalpy and Gibbs free energy changes for a standard reaction are denoted by the... 

The most useful expression for describing the variation of standard Gibbs free energy changes with temperature is ... 

The basic criterion for equilibrium with respect to a given chemical reaction is that the Gibbs free energy change associated with the progress of the reaction be zero. 

The standard Gibbs free energy change for a reaction refers to the process wherein the reaction proceeds isothermally, starting with stoichiometric quantities of reactants each in its standard state of unit activity and ending with products each at unit activity. In general it is nonzero and given by... 

As equation 2.4.8 indicates, the equilibrium constant for a reaction is determined by the temperature and the standard Gibbs free energy change (AG°) for the process. The latter quantity in turn depends on temperature, the definitions of the standard states of the various components, and the stoichiometric coefficients of these species. Consequently, in assigning a numerical value to an equilibrium constant, one must be careful to specify the three parameters mentioned above in order to give meaning to this value. Once one has thus specified the point of reference, this value may be used to calculate the equilibrium composition of the mixture in the manner described in Sections 2.6 to 2.9. 

At 25 °C the standard Gibbs free energy change for the reaction... 

An equilibrium constant is simply related to a standard Gibbs free energy change, as indicated by equation 2.4.7. 

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