Density of dry containing only N2 and O2 is 1.15g/L at 740 mm of Hg and 300 K. What is % composition of N2 by weight in the air?
We know that PV=nRT
Since, 1 atm= 760 mm of Hg
∴ 740 mm of Hg = 0.97 atm
M=dRTP=1.15×0.082×3000.97=29.16 g mol−1
Let M1 be mass fraction of N2
M2 be that of O2 M2=(1−M1)
M1×28+M2×32=29.16
On solving 4W1=2.83
W1=0.7008
So percentage of Nitrogen is 70.08