phase rule

nounPhysical Chemistry.

a law that the number of degrees of freedom in a system in equilibrium is equal to two plus the number of components less the number of phases. Thus, a system of ice, melted ice, and water vapor, being one component and three phases, has no degrees of freedom.: Compare variance (def. 4).

Origin of phase rule

First recorded in 1895–1900

Words Nearby phase rule

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use phase rule in a sentence

To these questions an answer can also be given with the help of the phase rule.
The Phase Rule and Its Applications | Alexander Findlay
As we shall learn, the phase rule enables us to give an answer to this question.
The Phase Rule and Its Applications | Alexander Findlay
The relations between the various systems, however, become perfectly clear and intelligible in the light of the phase rule.
The Phase Rule and Its Applications | Alexander Findlay
For other examples of the application of the phase rule to isomeric substances, see Journ.
The Phase Rule and Its Applications | Alexander Findlay

British Dictionary definitions for phase rule

phase rule

noun

the principle that in any system in equilibrium the number of degrees of freedom is equal to the number of components less the number of phases plus two: See also degree of freedom, component (def. 4)

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for phase rule

phase rule

A rule used in thermodynamics stating that the number of degrees of freedom in a physical system at equilibrium is equal to the number of chemical components in the system minus the number of phases plus the constant 2. Also called Gibbs phase rule See also phase transition state of matter.

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