Density of gas mixture

[John Cooper <jcooper@BUCKNELL.EDU>]

On Tue, 20 Jul 1999, Alvin V. Flores wrote:

> dry air is actually denser than moist air, contrary to what majority of
> our clients thought. in one particular session, i encountered a teacher
> who was quite hard to convince. kindly provide me with a thorough
> explanation.
   For a 'perfect' gas mixture, P = (Sum n) RT/V.
   But Density = (Sum n*FW)/V
   Since the formula weights of water, N2 and O2 are .018, .028 and .032,
replacing the latter two with water results in a lower density at
constant temperature and total pressure.

 John N. Cooper, Chemistry
 Bucknell University
 Lewisburg PA 17837-2005
 jcooper@bucknell.edu
 http://www.facstaff.bucknell.edu/jcooper
 VOX 570-577-3673    FAX 570-577-1739