In thermodynamics, the phase rule is a general principle governing multi-component, multi-phase systems in thermodynamic equilibrium.

Phase rule, law relating variables of a system in thermodynamic equilibrium, deduced by the American physicist J. Willard Gibbs. Systems in thermodynamic equilibrium are generally considered to be isolated from their environment, but many geological systems can be considered to obey the phase rule.

By providing a systematic approach to understanding the interplay between variables, Gibbs’ Phase Rule facilitates the exploration of various thermodynamic scenarios, from simple single-phase systems to more complex, multi-component systems.

Dec 16, 2021 · The phase rule is an important generalization dealing with the behavior of the heterogeneous system. It is possible to predict qualitatively by means of a diagram the effect of changing pressure, temperature, and concentration at equilibrium.

The relationship that Gibbs found between C C, P P, and F F is called Gibbs’ phase rule or just the phase rule. The phase rule applies to equilibrium systems in which any component can move freely between any two phases in which that component is present.

The phase rule describes the possible number of degrees of freedom in an enclosed system at equilibrium, in terms of the number of separate phases and the number of chemical constituents in the system. It was deduced by J.W Gibbs in the 1870s. Today, the phase rule is popularly known as the Gibbs phase rule all over the world.

13.1: The Gibbs Phase Rule for Multicomponent Systems 13.2: Phase Diagrams- Binary Systems 13.3: Phase Diagrams- Ternary Systems 13.4: Chapter 13 Problems

Aug 8, 2007 · Gibbs' Phase Rule provides the theoretical foundation, based in thermodynamics, for characterizing the chemical state of a (geologic) system, and predicting the equilibrium relations of the phases (minerals, melts, liquids, vapors) present as a function of physical conditions such as pressure and temperature.

Apr 13, 2022 · In Sec. 8.1.7, the Gibbs phase rule for a pure substance was written F = 3 − P F = 3 − P. We now consider a system of more than one substance and more than one phase in an equilibrium state. The phase rule assumes the system is at thermal and mechanical equilibrium.

The phase rule is a broad principle in thermodynamics that governs "pVT" systems in thermodynamic equilibrium (systems whose states are completely characterized by the variables pressure (p), volume (V), and temperature (T)).