Generalized Quasi-Random Lattice model for electrolyte solutions: Apparent and partial molal heat capacities

Abstract

Ionic solutions play an important role in many areas of technology and science, therefore understanding and predicting their thermodynamic behavior has been an essential research topic for an extended period of time. However, complexity and variety of real systems and the need for accurate representation of thermodynamic data hamper the development of models that are truly predictive over wide ranges of concentration, temperature and pressure conditions. In this regard, predictive potentialities of the Quasi-Random Lattice (QRL) model seem worthy of consideration.The QRL model, originally proposed for mean-activity/osmotic coefficients, was recently presented in a generalized form inclusive of formulae for partial/apparent molal enthalpies and volumes. This article follows and presents some further developments concerning partial and apparent molal heat capacities with application to various aqueous 1:1, 2:1, and 3:1 electrolytes. The semi-predictive character of QRL will be confirmed by present results and an improved procedure that yields the main QRL parameterization within a few steps will be illustrated. As a general remark, the experimental information required by QRL is very modest compared to the number of data points typically used with regression analysis.