Of a substance
B,
or
,
in a gaseous mixture is defined by
,
where
is the
partial pressure of B and
its
absolute activity.
Source:
See also:
PAC, 1994, 66, 533
(Standard quantities in chemical thermodynamics. Fugacities, activities and equilibrium constants for pure and mixed phases (IUPAC Recommendations 1994))
on page 539
PAC, 1984, 56, 567
(Physicochemical quantities and units in clinical chemistry with special emphasis on activities and activity coefficients (Recommendations 1983))
on page 571
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A.Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
doi:10.1351/goldbook.
, 
