For 10 min each, at 27 degrees celsius,from 2 identical holes,nitrogen and an unknown gas are leaked into a common vessel of 3 litre capacity. The resulting pressure is 4.18 bar and mixture contains 0.4 mole of nitrogen. WHat is the molar mass of the unknown gas?
pv=nRT
4.18*10^5*0.003=n*8.31*300 so n=0.503 moles so 0.103 moles unknown gas. The kinetic energies are the same(=3/2kT=1/2mv^2) so v=k/sqrt(m) the unknown gas diffuses at 1/4 the rate of nitogen so its mass must be 16 times greater 16*15=240g/mol