The density of nitrogen at STP is 1.25 kgm^-3. Find the r.m.s velocity of nitrogen molecule at 20 degree centigrade.

1 answer

Vrms = sqrt [3RT/M]

M is the molar mass, 28 g/mol
R = 8.317*10^7 erg/mole K
T = 293 K
You don't need to know the the density, but you could use it to get R/M.

V will be in cm/s with these units

For some background on kinetic theory, see
http://itl.chem.ufl.edu/2041_f97/lectures/lec_d.html