Excess compressibility entropy

Nor can the theory of regular solutions based on the simplified lattice model (cf. Ch. Ill) give any indication on the excess properties related to the equation of state such as the excess volume, the excess compressibility and hence the excess entropy and the excess specific heat all of which are closely related to the equation of state. In fact, no equation of state at all is introduced in this model. The lattice model can only be used to calculate the excess free energy and the excess enthalpy which should be equal in the zerbth approximation. However the experimental data invalidate this conclusion. 

The main excess properties are the free energy gE, enthalpy hB, entropy sE, and volume v (per molecule) data on other excess properties (specific heat, thermal expansion or compressibility) are rather scarce. In most cases gE, hE, sE, and vE have been determined at low pressures (<1 atm) so that for practical calculations p may be equated to zero their theoretical expressions deduced from Eqs. (33) and (34) are then as follows ... 

Entropy production during chemical change has been interpreted [7] as the result of resistance, experienced by electrons, accelerated in the vacuum. The concept is illustrated by the initiation of chemical interaction in a sample of identical atoms subject to uniform compression. Reaction commences when the atoms, compacted into a symmetrical array, are further activated into the valence state as each atom releases an electron. The quantum potentials of individual atoms coalesce spontaneously into a common potential field of non-local intramolecular interaction. The redistribution of valence electrons from an atomic to a metallic stationary state lowers the potential energy, apparently without loss. However, the release of excess energy, amounting to Au = fivai — fimet per atom, into the environment, requires the acceleration of electronic charge from a state of rest, and is subject to radiation damping [99],... 

The corresponding excess entropy, enthalpy, volume, energy, heat capacity and compressibility are readily obtained by use of the general thermodynamic formulae. 

The Carnahan-Starling equation of state is obtained from the virial expansion of a hard sphere fluid by curve-fitting and extrapolation. Table 1 compares values of the compressibility factor, Z, and the excess entropy, S, of a hard sphere fluid obtained from the Percus-Yevick equation and the Carnahan-Starling equation. 

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