Helmholtz free energy
E1010551
Helmholtz free energy is a thermodynamic potential that measures the useful work obtainable from a closed system at constant temperature and volume.
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
state function
ⓘ
thermodynamic potential ⓘ |
| alsoKnownAs |
Helmholtz energy
NERFINISHED
ⓘ
Helmholtz function NERFINISHED ⓘ |
| appliesTo |
closed systems
ⓘ
systems in contact with a heat bath at fixed temperature ⓘ |
| conditionForSpontaneity | process at constant T and V is spontaneous if ΔF < 0 ⓘ |
| conjugateTo |
chemical potential via particle number
ⓘ
pressure via volume ⓘ |
| definedByEquation | F = U - T S ⓘ |
| dependsOn |
canonical partition function
ⓘ
entropy ⓘ internal energy ⓘ temperature ⓘ |
| dimension | energy ⓘ |
| ensemble | canonical ensemble ⓘ |
| equilibriumCondition | ΔF = 0 at equilibrium for reversible processes at constant T and V ⓘ |
| extensiveOrIntensive | extensive quantity ⓘ |
| LegendreTransformOf | internal energy with respect to entropy ⓘ |
| mathematicalProperty | is a function of state variables T, V, N ⓘ |
| minimumPrinciple | equilibrium at constant T and V corresponds to minimum Helmholtz free energy ⓘ |
| namedAfter | Hermann von Helmholtz NERFINISHED ⓘ |
| naturalVariable |
particle number
ⓘ
temperature ⓘ volume ⓘ |
| perMoleForm | molar Helmholtz free energy ⓘ |
| perParticleForm | f = F/N ⓘ |
| physicalMeaning | maximum useful work obtainable from a closed system at constant temperature and volume ⓘ |
| relatedTo |
Gibbs free energy
ⓘ
enthalpy ⓘ grand potential ⓘ internal energy ⓘ |
| SIBaseUnits | kg·m^2·s^-2 ⓘ |
| statisticalMechanicsExpression | F = -k_B T ln Z ⓘ |
| symbol |
A
ⓘ
F ⓘ |
| thermodynamicDifferential | dF = -S dT - p dV + μ dN (for single component system) ⓘ |
| unit | joule ⓘ |
| useCondition |
constant temperature
ⓘ
constant volume ⓘ |
| usedIn |
chemical thermodynamics
ⓘ
condensed matter physics ⓘ statistical mechanics ⓘ thermodynamics ⓘ |
| usedToDerive |
compressibility
ⓘ
equations of state ⓘ response functions such as heat capacities ⓘ thermal expansion coefficient ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.