Excess compressibility enthalpy

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

Here Y denotes a general bulk property, Tw that of pure water and Ys that of the pure co-solvent, and the y, are listed coefficients, generally up to i=3 being required. Annotated data are provided in (Marcus 2002) for the viscosity rj, relative permittivity r, refractive index (at the sodium D-line) d. excess molar Gibbs energy G, excess molar enthalpy excess molar isobaric heat capacity Cp, excess molar volume V, isobaric expansibility ap, adiabatic compressibility ks, and surface tension Y of aqueous mixtures with many co-solvents. These include methanol, ethanol, 1-propanol, 2-propanol, 2-methyl-2-propanol (tert-butanol), 1,2-ethanediol, tetrahydrofuran, 1,4-dioxane, pyridine, acetone, acetonitrile, N, N-dimethylformamide, and dimethylsulfoxide and a few others. 

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 ... 

Energies, Excess Enthalpies, Excess Volumes, and Isothermal Compressibilities of Cyclohexane + 2,3-Dimethylbutane , J. Client. Thermodyn., 6, 35-41 (1974). J. B. Ott, K. N. Marsh, and R. H. Stokes, Excess Enthalpies, Excess Gibbs Free Energies, and Excess Volumes for (Cyclohexane + n-Hexane), and Excess Gibbs Free Energies and Excess Volumes for (Cyclohexane + Methylcyclohexane) at 298.15 and 308.15 K , J. Chem. Thermodyn., 12, 1139-1148 (1980). 

Analogously to Eq. (6.60), the enthalpy of a liquid mixture can be evaluated by taking the excess enthalpy into account. Again, the liquid enthalpy refers to a saturated liquid, enthalpy changes due to further compression are neglected. 

Ewing, M. B. Marsh, K. N. Excess Gibbs free energies, excess enthalpies, excess volumes, and isothermal compressibilities of cyclohexane + 2,3-dimethylbutane J. Chem. Thermodyn. 1974, 6, 35-41... 

Hahn, G., van Nhu, N., Siddiqi, M.A., and Svejda, P. (1990) Excess volume, isothermal compressibility, and excess enthalpy of the binary liquid system trichlorofluoromethane... 

First of all we give the general expressions for the excess free energy, enthalpy and compressibility at zero pressure. It follows directly from (9.3.8) that... 

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