Solution of the compressibility equation of the adhesive hard-sphere model for mixtures
1975; Elsevier BV; Volume: 11; Issue: 3 Linguagem: Inglês
10.1016/0301-0104(75)80055-3
ISSN1873-4421
Autores Tópico(s)Chemical Thermodynamics and Molecular Structure
ResumoThe solution of the generalized equations of Percus and Yevick is obtained for mixtures of molecules interacting via the adhesive hard-sphere potential. It is shown that the possibility of a discontinuous phase or fluid-fluid transition appears only in such binary systems where the adhesion acts between like particles of at least one of the components. The found distribution functions are used to obtain from the compressibility equation the expression for the pressure of a mixture consisting of v components in arbitrary concentration. The pressure, chemical potential and other thermodynamic properties are calculated explicitly in the limit when several components (the solutes) are dilute and one component (the solvent) is in its “liquid” phase. The solubility of substances of small molecules is shown to increase when the temperature T rises. The same regularity is found in the case when the interaction between solvent and solute consists only of a hard-sphere potential. In the general case of the presence of adhesion between solvent and solute molecules and for arbitrary ratio of particles sizes a minimum appears on the solubility cuves versus T. If the attraction is sufficiently big the drop in the solubility may be very sharp and reach the value zero at a certain temperature. The results obtained are qualitatively supported by examples from experiment.
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