Gibbs energy residual

Evaluation of the integrals requires an empirical expression for the temperature dependence of the ideal gas heat capacity, (3p (8). The residual Gibbs energy is related to and by equation 138 ... 

According to equation 132, is the residual Gibbs energy, G. The dimensionless mXio fjP is a new property called the fugacity coefficient, ( ). ... 

Analogous to the defining equation for the residual Gibbs energy is the definition of a partial molar residual Gibbs energy (eq. 161) ... 

The residual Gibbs energy and the fugacity coefficient are useful where experimental PVT data can be adequately correlated by equations of state. Indeed, if convenient treatment or all fluids by means of equations of state were possible, the thermodynamic-property relations already presented would suffice. However, liquid solutions are often more easily dealt with through properties that measure their deviations from ideal solution behavior, not from ideal gas behavior. Thus, the mathematical formahsm of excess properties is analogous to that of the residual properties. 

All eight parameters depend on composition moreover, parameters Co, b, and y are for some applications treated as functions of X By Eq. (4-171), the residual Gibbs energy is... 

In order to obtain an expression for the excess Gibbs energy, we first define g(a), g(c, and gW as the residual Gibbs energies per mole of cells of central anion, central cation and central solvent molecule, respectively. These Gibbs energies are related to the local mole fractions as follows ... 

The molar excess Gibbs energy may now be derived by summing the changes in residual Gibbs energy resulting when xm moles of solvent are transfered from the solvent reference state to their cells in the mixture, and when xa moles of anions and xc moles of cations are transfered from the electrolyte reference state to their respective cells in the mixture. The expression is ... 

Thus the residual Gibbs energy serves as a generating function for the other residual properties, and here we do have a direct link with experiment. It is provided by Eq. (6.37), written... 

The residual Gibbs energy and the fugacity coefficient are directly related to experimental PVT data by Eqs. (6.40) and (11.20). Where such data can be... 

The definition of the residual Gibbs energy as given by Eq. (6.32) is readily combined with Eq. (11.2), the definition of a partial property, to provide a defining equation for the partial residual Gibbs energy. Thus, upon multiplication by n, Eq. (6.32) becomes... 

By Eq. (11.31), G - is the partial residual Gibbs energy Gf the dimensionless ratio fi/yiP is called the fugacity coefficient of species i in solution, and is given the symbol < j. Then... 

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