Journal: Transactions of The Luventicus Academy (Trans. Luv. Acad.)

ISSN 1666-7581 (online)

ISSN 1666-7573 (printed)

Volume: 2002

Issue: 1 (March)

Paper: 1

Pages: 1-14

Internal use code: 02TLA001iii

PDF file: ftp.luventicus.org/papers/02TLA001iii.pdf

Title: III. Three fundamental theorems on Chemical Thermodynamics

Author: Juan José Luetich

Abstract: Chemical Thermodynamics is the uniied theory of physical and chemical transitions. This work presents three theorems on which the whole subject can be grounded. The irst of them reveals the existing connection between the Lagrange multipliers method of the non-stoichiometric formulation and the homogeneity condition which is implicit in most of thermodynamic equations. However, this condition is less restrictive than the homogeneity of the system, i.e. of all its properties; it solely deals with the Gibbs energy homogeneity with respect to the composition vector. Thus, equations can also be applied to equilibrium multi-phase systems. The second one looks into the element deinition used in the physical approach to chemical equilibrium problems: element potentials do not depend on the particles state because the Gibbs energy is an homogeneous function of the element composition vector. The third one shows the relationship between the deinition of element potential and the dynamics of equilibrium at the microscopic level: this deinition corresponds to a change in the element particles number in any state—element potentials are homogeneous magnitudes of zeroth degree. These three theorems are different ways to present the same idea: the concept of homogeneity and its consequences.

Keywords: Gibbs energy; Chemical Thermodynamics; Lagrange multipliers; Legendre transformations; dynamic equilibrium