Excess mixing property

Eugster H. R, Albee A. L., Bence A. E., Thompson J. B. Jr., and Walbaum D. R. (1972). The two phase region and excess mixing properties of paragonite-muscovite crystalline solutions. J. Petrol, 13 147-179. 

Still, the investigations of the excess mixing properties are very useful in examining the possibility of the formation of solvent-cosolvent complex adducts in solution [20]. The dependence of these properties on temperature and on composition of the liquid mixture permits their continuous variation and can provide much useful information, otherwise hardly detectable, about the complex species [21]. 

This book contains approximately 6000 references to excess mixing property data for mixtures of all types, including electrolyte, non-electrolyte, and metallurgical systems. The appropriate references to the literature are given for each mixture. The coverage of materials encompasses the entire periodic chart and also includes ternary, quaternary, and multi-component mixtures. 

Wisniak, J. Tamir, A. "Mixing and Excess Thermodynamic Properties. A Literature Source Books" Elsevier Scientific Publishing Co., New York, 1978. 

The excess thermodynamic properties for (cyclohexane + hexane) were obtained from the following sources Excess enthalpies come from K. N. Marsh and R. H. Stokes, Enthalpies of Mixing of n-Hexane + Cyclohexane at 25 °C , J. Chem. Thermodyn., 1, 223-225 (1969) and M. B. Ewing and K. N. Marsh, The Enthalpy of Mixing of n-Hexane + Cyclohexane at... 

Wisniak, J., and Tamir, A. (1982, 1986). Mixing and Excess Thermodynamic Properties A Literature Source Book. Amsterdam Elsevier. 

Thus, an excess thermodynamic property is also the difference between the thermodynamic property for mixing the real and ideal solutions. For the Gibbs free energy, this becomes, using Eq. (3) and Eq. (35) of Chapter 8,... 

For most physical properties in dilute solutions, the estimates can be made without the APex term. When adding the excess-mixing terms to the equations, one is dividing the summation 2]ion-ion into three terms ... 

We refer to a mixture for which Equation 58 or 59 is satisfied as an ideal mixture. Clearly this concept of an ideal mixture is an idealization that is not realized in practice. Real mixtures will show deviations from the ideal results. However, the properties of an ideal mixture are convenient reference states for thermodynamic properties. For example, it is conventional to use excess thermodynamic properties of mixing that are defined as the difference between the thermodynamic property of the mixture and those of an ideal mixture of the components at the same temperature and pressure. 

J. Wisniak and A. Tamir, Mixing and Excess Thermodynamic Properties... 

As these cosolvents contain both hydrophilic and hydrophobic groups, the same molecule can induce opposite effects in water. The hydrophilic part can interact with water to form strong HBs, while the hydrophobic part may induce cooperative ordering in the system by a hydrophobic hydration effect. These two effects combine together to regulate the extensive HB network of water in their aqueous binary mixtures that is reflected in strong, often anomalous non-ideal behavior in many physical properties such as viscosity, density, dielectric constant, excess mixing volume, surface tension, heat of formation, etc. 

Ejqrosme to excessive heat and sunlight Premature ageing, cross-linking of resin and increased viscosity Poor mixing properties, low mould strengths and poor resistance to high temperatures Fining defects... 

Recently Guermouche and Vergnaud measured the activity coefficients of normal alkanes in squalane at various temperatures in order to determine the excess thermodynamic properties of mixing. Unfortunately the results, obtained from conventional atmospheric g.l.c. (pi 180 kPa), do not always agree with the static and medium-pressure g.l.c. results quoted by Cruickshank et al. ... 

The mixing properties of garnet components and many other rock-forming solid solutions is an on-going problem, and we can leave resolution of the problems of grossular-pyrope to the experts. The point made here is simply that determinations of excess properties can be made by calorimetry, measuring phase compositions, and X-ray work, and that these can be combined into values of Wc and hence of activity coefficients. None of this is easy to do. 

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