Re: What is the speed of an atom of nitrogen in an every-day room?

Assuming the gas to be ideal, and room temperature to be 300K (equivalent 
to 27 degrees C), 

kinetic energy = (mv*v)/2 = 3KT/2

rearranging this gives:
v = sqrt(3KT/m)

where 	v = speed of particles
        K = Boltzmann constant = 1.381exp-23 (Joules per Kelvin)
	T = Temperature of gas
	m = mass of particles

the mass one atom of Nitrogen is 14u = 2.3247exp-26 (Kilograms)

substituting this into the equation for v gives:
	v = sqrt {(3*1.381exp-23*300) / 2.3247exp-26}
	v = 731 metres per second.

***************************************************************************
However it is MOLECULAR nitrogen which is found in the atmosphere not 
atomic nitrogen…

The mass of one molecule of Nitrogen is 4.65exp-26 (Kilograms)

substituting this into the equation for v gives:
	v = sqrt {(3*1.381exp-23*300) / 4.65exp-26}
	v = 517 metres per second.

***************************************************************************
For more information see:
Kinetic theory and ideal gases.