# List of thermodynamic properties

Within thermodynamics, a physical property is any property that is measurable, and whose value describes a state of a physical system. Some constants, such as the ideal gas constant, *R*, do not describe the state of a system, and so are not properties. On the other hand, some constants, such as *K _{f}* (the freezing point depression constant, or cryoscopic constant), depend on the identity of a substance, and so may be considered to describe the state of a system, and so may be considered physical properties.

"Specific" properties are expressed on a per mass basis. If the units were changed from per mass to, for example, per mole, the property would remain as it was (i.e., intensive or extensive).

**Regarding Work and Heat**

Work and heat are not thermodynamic properties, but rather *process quantities:* flows of energy across a system boundary. Systems do not *contain* work, but can *perform* work, and likewise, in formal thermodynamics, systems do not *contain* heat, but can *transfer* heat. Informally, however, a difference in the energy of a system that occurs solely because of a difference in its temperature is commonly called *heat*, and the energy that flows across a boundary as a result of a temperature difference is "heat".

Altitude (or elevation) is usually not a thermodynamic property. Altitude can help specify the location of a system, but that does not describe the state of the system. An exception would be if the effect of gravity needed to be considered in order to describe a state, in which case altitude could indeed be a thermodynamic property.

Property | Symbol | Units | Extensive? | Intensive? | Conjugate | Potential? |
---|---|---|---|---|---|---|

Activity | – | |||||

Chemical potential | kJ/mol | Particle number |
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Compressibility (adiabatic) | , | Pa^{−1} |
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Compressibility (isothermal) | , | Pa^{−1} |
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Cryoscopic constant^{[1]} |
K·kg/mol | |||||

Density | kg/m^{3} |
|||||

Ebullioscopic constant | K·kg/mol | |||||

Enthalpy | J | |||||

Specific enthalpy | J/kg | |||||

Entropy | J/K | Temperature | ||||

Specific entropy | J/(kg K) | |||||

Fugacity | N/m² | |||||

Gibbs free energy | J | |||||

Specific Gibbs free entropy | J/(kg K) | |||||

Gibbs free entropy | J/K | |||||

Grand / Landau potential | J | |||||

Heat capacity (constant pressure) | J/K | |||||

Specific heat capacity (constant pressure) |
J/(kg·K) | |||||

Heat capacity (constant volume) | J/K | |||||

Specific heat capacity (constant volume) |
J/(kg·K) | |||||

Helmholtz free energy | , | J | ||||

Helmholtz free entropy | J/K | |||||

Internal energy | J | |||||

Specific internal energy | J/kg | |||||

Internal pressure | Pa | |||||

Mass | kg | |||||

Particle number | – | Chemical potential |
||||

Pressure | Pa | Volume | ||||

Temperature | K | Entropy | ||||

Thermal conductivity | W/(m·K) | |||||

Thermal diffusivity | m²/s | |||||

Thermal expansion (linear) | K^{−1} |
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Thermal expansion (area) | K^{−1} |
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Thermal expansion (volumetric) | K^{−1} |
|||||

Vapor quality^{[2]} |
– | |||||

Volume | m^{3} |
Pressure | ||||

Specific volume | m^{3}/kg |

## See also

- Dimensionless numbers
- Thermodynamic databases for pure substances
- Thermodynamic variable
- Conjugate variables