Chemical Thermodynamics: A Journey of Many Vistas

Abstract

Chemical thermodynamics is of central importance in chemistry, physics, the biosciences and engineering. It is a highly formalized scientific discipline of enormous generality, providing a mathematical framework of equations (and a few inequalities), which yields exact relations between macroscopically observable thermodynamic equilibrium properties of matter and restricts the course of any natural process. While these aspects alone are already of the greatest value for practical applications, in conjunction with judicially selected molecular-based models of material behavior, that is to say by using concepts from statistical mechanics, experimentally determined thermodynamic quantities contribute decisively towards a better understanding of molecular interactions and hence of real macroscopic systems. A plenary lecture affords the lecturer an opportunity to survey a few reasonably large sub-areas of the fields he works/worked in and to reflect on them from the perspective of many years of research. The general subject I selected for this review, i.e. chemical thermodynamics of liquid nonelectrolytes (pure or mixed), is vast. Over the last decades, the field’s impressive growth has been stimulated by the continuously increasing need for thermophysical property data and phase equilibrium data in the applied sciences, and it has greatly profited by advances in experimental techniques, by advances in the theory of liquids in general, and by advances in computer simulations of reasonably realistic model systems in particular. Specifically, I shall focus on just three topics of increasing complexity: (1) heat capacities and related quantities of fairly simple molecular liquids, predominantly at or near orthobaric conditions; (2) chemical thermodynamics of binary liquid mixtures containing one strongly dipolar aprotic component; (3) caloric properties of dilute solutions of nonelectrolytes, with emphasis on properties of aqueous solutions at infinitedilution (which are of importance in biophysical chemistry).