enthalpy

Measure of energy in a thermodynamic system; thermodynamic quantity equivalent to the total heat content of a system

EntityQ161064

Subclass of: physical quantity
, extensive quantity
, thermodynamic potential
+1 more

Overview

From Wikipedia, the free encyclopedia · Read full article · Text CC BY-SA 4.0

Enthalpy is the sum of a thermodynamic system's internal energy and the product of its pressure and volume. It is a state function in thermodynamics used in many measurements in chemical, biological, and physical systems at a constant external pressure, which is conveniently provided by Earth's ambient atmosphere. The pressure–volume term expresses the work that was done against constant external pressure to establish the system's physical dimensions from to some final volume , i.e. to make room for itself by displacing its surroundings. The pressure-volume term is very small for solids and liquids at common conditions, and fairly small for gases. Therefore, enthalpy is a stand-in for energy in chemical systems; bond, lattice, solvation, and other chemical "energies" are actually enthalpy differences. As a state function, enthalpy depends only on the final configuration of internal energy, pressure, and volume, not on the path taken to achieve it.

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70 statements · 20% with external sources · numbers in brackets are citations

Defining formula: H = U + p V
2
Sources
1.Stated in ISO 80000-5:2007 Quantities and units — Part 5: Thermodynamics
2.Stated in ISO 80000-5:2019 Quantities and units — Part 5: Thermodynamics
View statement on Wikidata ↗
ISQ dimension: \mathsf{L}^2 \mathsf{M} \mathsf{T}^{-2}
In defining formula: H symbol represents: enthalpy
U symbol represents: internal energy
p symbol represents: pressure
V symbol represents: volume
Quantity symbol (LaTeX): H unicode character: H
1
Sources
1.Stated in ISO 80000-5:2019 Quantities and units — Part 5: Thermodynamics
View statement on Wikidata ↗
Different from: entropy
Recommended unit of measurement: joule
2
Sources
1.Stated in ISO 80000-5:2019 Quantities and units — Part 5: Thermodynamics
2.Stated in ISO 80000-5:2007 Quantities and units — Part 5: Thermodynamics
View statement on Wikidata ↗
kilogram square metre per square second
1
Sources
1.Stated in ISO 80000-5:2019 Quantities and units — Part 5: Thermodynamics
View statement on Wikidata ↗
Studied by: thermodynamics
Invariant under: isenthalpic process

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36 identifiers linking enthalpy across the web's reference databases

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Source last edited October 2, 2026. AIDB refreshes this page daily.

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AIDB. (2026). enthalpy (Q161064). Retrieved from https://aidb.si/e/enthalpy-Q161064