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**tadchem**

wrote:

snip

For the physicists: what's the AVERAGE velocity of the nitrogen
molucules at 25 degree C & atmospheric pressure ?

From kinetic molecular theory of gases:

The *most probable* velocity (peak of the distribution)
c(p) = SQRT(2*k*T/m)

The average scalar velocity
c-bar = SQRT(8*k*T/pi*m)

The velocity of the molecule with average kinetic energy
SQRT(c^2-bar) = SQRT(3*k*T/m)

where k = Boltzmann's constant, T is absolute temperature, and m is
molecular mass.

Note that pressure is not a significant system variable in these
results - only temperature. Pressure *does* contribute to other
quantities such as collision frequencies and mean free path.

FWIW, c-bar for a nitrogen molecule at 25° C is about 1.31*10^5
cm/sec.

Tom Davidson
Richmond, VA