Question

An unknown gas diffuse four times as quickly as oxygen calculate tha mass of tha gas.

Answer 1

We use the Graham's law of diffusion, which says rate of diffusion of a gas is inversely proportional to the square root of Molecular mass

$\frac{r_{1} }{r_{2}} = \sqrt{\frac{M_{2}}{M_1}}$

let r1 be rate of unknown gas and M1 it's molecular mass.

r1/r2 =4 (given)

M2/M1=16

M1=M2/16

M2 is molecular mass of oxygen, hence =32

M1= 2 g