Heats of Solution from Experimental Data

Heats of Solution from Experimental Data Apparent Molar Enthalpy 

Calorimetric data for solutions are handled in a number of different ways, which can be confusing. In addition to integral and differential heats of solution and the partial molar enthalpy of solution, we also have the apparent partial molar enthalpy, the relative partial molar enthalpy, and the relative apparent partial molar enthalpy. To see how these terms cirise, consider the following. 

According to equation (9.4) the enthalpy of a two-component solution can be split into partial molar enthalpy terms for the solvent and solute. 

Again considering the case where ri2 0 we can write from (9.26) 

Thus measuring (j)H and extrapolating to infinite dilution would seem to offer a method for determining the most commonly desired quantity. Except for one problem, that is. As emphasized in earlier chapters, absolute values for H and hence 4 h, etc. are unknown and unknowable, since the definition of H is 

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