The Gibbs phase rule relates the number of degrees of freedom to the number of components and number of phases in a system at thermodynamic equilibrium. In determining the number of components, one must determine the number of independent reactions and the number of stoichiometric constraints.
Textbooks focus on the problem of determining the number of independent reactions.
This paper discusses the stoichiometric constraints in multiphase reactive systems. It is shown that two simple, seemingly similar systems can differ in their number of components. Interrelationships between Components and Phases J. Chem. All rights reserved.