# List of thermodynamic properties

Thermodynamic properties and their characteristics
Property Symbol Units Extensive? Intensive? Conjugate Potential? State
qty.
?
Process
qty.
?
Activity $a$  –
Altitude m
Chemical potential $\mu_i$ kJ/mol Particle
number $N_i$
Compressibility (adiabatic) $\beta_S$, $\kappa$ Pa−1
Compressibility (isothermal) $\beta_T$, $\kappa$ Pa−1
Cryoscopic constant[1] $K_f$ K·kg/mol
Density $\rho$ kg/m3
Ebullioscopic constant $K_b$
Enthalpy $H$ J
Specific enthalpy $h$ J/kg
Entropy $S$ J/K Temperature $T$ (entropic)
↳ Specific entropy $s$ J/(kg K)
Fugacity $f$ N/m²
Gas constant $R, \bar R$ J/K
Specific gas constant
(for a particular substance)
$R_S$ J/(kg K)
Gibbs free energy $G$ J
↳ Specific Gibbs free entropy $g$ J/(kg K)
Gibbs free entropy $\Xi$ J/K (entropic)
Grand / Landau potential $\Omega$ J
Heat $Q$ J
Heat capacity (constant pressure) $C_p$ J/K
Specific heat capacity
(constant pressure)
$c_p$ J/(kg·K)
Heat capacity (constant volume) $C_v$ J/K
Specific heat capacity
(constant volume)
$c_v$ J/(kg·K)
Helmholtz free energy $A$, $F$ J
Helmholtz free entropy $\Phi$ J/K (entropic)
Internal energy $U$ J
Specific internal energy $u$ J/kg
Internal pressure $\pi _T$ Pa
Mass $m$ kg
Particle number $N_i$  – Chemical
potential $\mu_i$
Pressure $p$ Pa Volume $V$
Temperature $T$ K Entropy $S$
Thermal conductivity $k$ W/(m·K)
Thermal diffusivity $\alpha$ m²/s
Thermal expansion (linear) $\alpha_L$ K−1
Thermal expansion (area) $\alpha_A$ K−1
Thermal expansion (volumetric) $\alpha_V$ K−1
Vapor quality[2] $\chi$  –
Volume $V$ m3 Pressure $P$
Specific volume $v$ m3/kg
Work $W$ J

Specific properties are expressed on a per mass basis; in some circumstances other dimensions could be used, such as per-mole.

Regarding Work and Heat:

Note that work and heat above are listed as process quantities: They are not thermodynamic properties, but 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".