Molar volume of an ideal gas at 0 °C and 1 atm

V_{\mathrm{m}}^{\,\mathrm{atm}} = 22.41396954\ \text{L/mol}

Value	22.41396954 L/mol
Status	Exact by definition — no uncertainty
Source	CODATA 2022 (exact in the 2019 SI)
Categories	Thermodynamic Chemistry

Learning zone

This is the 22.4 L/mol every chemistry student memorises, stated properly: 22.413 969 54 L/mol at 273.15 K and 101.325 kPa. It is exact, because R is exact and both reference conditions are defined values.

It survives because a great deal of gas engineering is still quoted at one atmosphere — normal cubic metres, standard cubic feet, gas chromatography carrier flows, respiratory volumes. If you use it, say so: the same mole at 25 °C and 1 atm takes 24.465 L, and at IUPAC's current 0 °C and 1 bar it takes 22.711 L. Quoting a molar volume with no temperature and pressure attached is the fastest way to be 10 % wrong.

Used by these solvers

Gas Volume at STP

V = n\,V_m

Ideal Gas Law

P V = n R T

Combined Gas Law

\frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2}