Gibbs phase rule
E517574
The Gibbs phase rule is a fundamental thermodynamic principle that relates the number of components and phases in a system to its degrees of freedom, determining how many variables can be independently varied without changing the number of phases in equilibrium.
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
equilibrium criterion
ⓘ
physical law ⓘ thermodynamic rule ⓘ |
| appliesTo |
closed systems
ⓘ
heterogeneous systems at equilibrium ⓘ multicomponent systems ⓘ |
| assumes |
chemical equilibrium
ⓘ
intensive variables uniform within each phase ⓘ mechanical equilibrium ⓘ no external fields ⓘ thermal equilibrium ⓘ |
| category | equilibrium thermodynamics ⓘ |
| condensedForm | F = C − P + 1 ⓘ |
| condensedFormAppliesTo |
systems at constant pressure
ⓘ
systems where gas phase is neglected ⓘ |
| coreConcept | intensive variables minus constraints give degrees of freedom ⓘ |
| defines |
C as number of components
ⓘ
F as number of degrees of freedom ⓘ P as number of phases ⓘ |
| describes | relationship between components phases and degrees of freedom ⓘ |
| field |
chemical engineering
ⓘ
materials science ⓘ physical chemistry ⓘ thermodynamics ⓘ |
| hasVariant | condensed phase rule ⓘ |
| implies |
maximum number of coexisting phases is C + 1 in condensed systems
ⓘ
maximum number of coexisting phases is C + 2 in non-condensed systems ⓘ |
| introducedIn | 19th century ⓘ |
| namedAfter | Josiah Willard Gibbs NERFINISHED ⓘ |
| relatedTo |
Gibbs free energy minimization
ⓘ
chemical potential equality in phases ⓘ phase equilibrium conditions ⓘ |
| relatesQuantity |
degrees of freedom
ⓘ
number of components ⓘ number of phases ⓘ |
| requires |
counting of phases in equilibrium
ⓘ
knowledge of independent components ⓘ |
| symbolicForm | F = C − P + 2 ⓘ |
| taughtIn |
materials thermodynamics courses
ⓘ
physical chemistry curricula ⓘ undergraduate thermodynamics courses ⓘ |
| usedFor |
analyzing azeotropes
ⓘ
analyzing eutectic reactions ⓘ analyzing invariant points ⓘ analyzing peritectic reactions ⓘ constructing phase diagrams ⓘ determining variance of a system ⓘ predicting number of coexisting phases ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.