Resolution of an Instructive Gibbs-Energy Problem from the Prigogine-Defay-Everett Framework of Chemical Thermodynamics

Gibbs-energy is a very useful concept in chemistry. The application of this thermodynamic potential leads to an elegant explanation as well as to a valuable prediction of the behavior of a given physicochemical system. Schomaker & Waser, J. Chem. Educ. 1988, 65(11): 968–9, have proposed an instructive Gibbs-energy problem. These authors present various treatments to solve the problem, i.e. three different possibilities all proceeding from a two-variable approach. Here, we offer an alternative resolution to this problem, which has been inspired on the Prigogine-Defay-Everett chemical thermodynamics framework (i.e. a three-variable approach). In this way, we have pointed up the strength and elegance of this formulation. The resolution of this problem through the Prigogine-Defay-Everett approach could be very illustrative in a first course of chemical thermodynamics.