Gibbs energy of dissolution

The solubility of an ionic solute, Sca, may be expressed in terms of its solubility product, The equilibrium between a pure solid salt, Cv+Av and its saturated solution in a solvent where it is completely dissociated to ions (generally having e > 40 see section 2.6) is governed by its standard molar Gibbs energy of dissolution... 

The standard molar Gibbs energy of dissolution is related directly to the activity of the dissolved solute in the saturated solution of a crystalline or liquid solute, assat. 

Abstract - The standard potentials of the reaction steps for the reduction of TiCLi in alkali chlorides were calculated from transient electrochemical techniques. It is shown that the stability ranges of the various oxidation states of titanium depend on the composition and temperature of the solvent. The presence of strong chloride ion donors, such as cesium chloride, enhances the stability of the high oxidation states. The results are interpreted in terms of formation of chlorocomplexes. The thermodynamic properties of solutes were calculated and the Gibbs energy of dissolution of the titanium salts determined. 

TABLE II. Standard Gibbs energy of formation, AGg, of TiCLj, TiCla and TiCl2 dissolved in various electrolytes. Standard Gibbs energy of dissolution, AG gjss- AG° in kJ mole" and T Kelvin. 

The Gibbs energy of dissolution of the three compounds in the electrolytes are calculated and reported in Table II. For titanium tetrachloride, it corre-... 

The relationship between these two functions is as follows AicG = AssG + AiG - A2G, where AiG and A2G are the related Gibbs energies of dissolution of the monomer and polymer in the given solution. In an inert solvent AiG A2G and then AicG AssG, indicated above simply as AG. 

Solubility product — is the equilibrium constant Ksp of dissolution of a salt. Solubility products can be determined by direct determination of the -> concentrations of the dissolved salt, provided the activity constants are practically 1.0, or otherwise known. Solubility products can also be calculated from the standard -> Gibbs energies of formation AfG" of the species. 

Figure 6.1. Reactivity in liquid metal M/oxide AnOm systems above a certain value of AGr/(RT), where AG, given by equation (6.8.b) is a Gibbs energy for dissolution of AnOm oxide in liquid metal M, a new oxide (MpOq) precipitates at the interface. (Note that the reactivity scale in Figure 6.2 is built using the extrapolated part of the curve (dotted line) corresponding to the equilibrium between the liquid metal and the initial oxide A Om).

Microcalorimeters have the ability of directly measuring the order of the reaction (n), the rate constant (k), the reaction enthalpy (Ar//), and the equilibrium constant (ATeq). " For example, solution microcalorimetry may be used to determine the free energy of dissolution of a solid compound, which is particularly important in pharmaceutical research for dissolution studies and in the determination of the relative thermodynamic stability of polymorphs. " The change in the Gibbs-Helmholtz free energy, AGsoi, on dissolution is... 

The standard Gibbs energy may be obtained from the standard Gibbs energies of fusion and dissolution of solid AB. 

Fig. 15.2. Gibbs free energy of dissolution for ideal binary solutions from 0 to 2000 K. Gideai diaaoVn and Gidaal soi n decreasB markedly at higher T, making solutions more stable.

During this reaction, the Gibbs energy of both A and B become lower. If the mixing line lies above the straight line joining G and Gg, then would be positive, the dissolution reaction (7.21) would not be spontaneous, and no solution wouid form - A and B would be immiscible, like oil and water. 

The total Gibbs energy of polymer dissolution is the sum of the interac-... 

FIGURE 12.3 Gibbs energy of polymer dissolution as a function of the volume fraction i of the polymer in the solution. The range over which phase separation occurs is indicated. 

Gibbs free energy of dissolution for the process in the cliroma-tographic column... 

A thermochemical study of natural gismondine, garronite, and amicite was performed by [0301]. Experimentally, the enthalpies of formation of minerals from elements were determined with a calorimetry technique of dissolution, in the 2 Pb0 B203 melt, at 973 K. The entropies and Gibbs energies of mineral formation from elements were evaluated - Table 8. 

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