Question

The molar mass of an unknown gas was measured by an effusion experiment. It was found that it took 60 s for the gas to effuse, whereas nitrogen gas required 48 s. The molar mass of the gas is ________

Answer 1

Answer:

The molar mass of the gas is 44 g/mol

Explanation:

It is possible to solve this problem using Graham's law that says: Rates of effusion are inversely dependent on the square of the mass of each gas. That is:

$\frac{r_1}{r_2} =\frac{\sqrt{M_2} }{\sqrt{M_1} }$

If rate of effusion of nitrogen is Xdistance / 48s and for the unknown gas is X distance / 60s and mass of nitrogen gas is 28g/mol (N₂):

$\frac{X/48s}{X/60s} =\frac{\sqrt{M_2} }{\sqrt{28g/mol} }$

6,61 = √M₂

44g/mol = M₂

The molar mass of the gas is 44 g/mol

I hope it helps!