The universal gas constant, also known as the molar or ideal gas constant, is
R* = 8.3144621(75) J mol-1 K-1.
The gas constant for a particular gas is
is the molecular weight
of the gas. For a mixture, the "molecular weight" is a weighted mean of the molecular weights of the components:
, · · ·, mn
are the molecular weights of the n
gases, and f1
, · · ·, fn
are their masses relative to the total mass of the mixture. The gas constant for dry air
The gas constant for water vapor
For moist air
, the variable percentage of water vapor is taken into account by retaining the gas constant for dry air while using the virtual temperature
in place of the temperature
. See also Boltzmann's constant
Mohr, P. J., B. N. Taylor, and D. B. Newell, 2012: CODATA recommended values of the fundamental physical constants: 2010. J. Phys. Chem. Ref. Data, 41, 043109, doi:10.1063/1.4724320.
Wallace, J. M., and P. V. Hobbs, 1977: Atmospheric Science: An Introductory Survey. Academic Press, 350 pp.
(Term edited 5/22/2014)