3) The rate of diffusion of a gas x is found to be 0.5 times that of methane(CH4). Work out the molecular mass of gas x. Given (C=12.0, H=1.0)
Solution
Step I
Graham's Law of diffusion
    Rate of diffusion of gas x2
    Rate of diffusion of methane     =
    molecular mass of CH4
    Molecular mass x
Step II
work out the molecular mass of the methane (CH ) by adding atomic masses.
C =
X 1 = 12 ;   4(H) =
X 4 = 4 ;   12 +
=
Step III
Substitute the rates of diffusion and molecular mass.
0.5/1=√/x