Chapter 6, Problem 85E

Interpretation Introduction

Interpretation:

The time taken by helium balloon to shrink to half of its original volume at STP should be determined.

Concept introduction:

According to the Graham’s law of effusion, rate of effusion of any gas is always inversely proportional to the square root of the mass of gaseous particles.

The mathematical expression for this law is:

$\frac{\text{Rate of effusion of gas 1}}{\text{Rate of effusion of gas 2}}\text{=}\sqrt{\frac{{\text{M}}_{\text{2}}}{{\text{M}}_{\text{1}}}}$

Here, M₁ and M₂ represent the molar mass of gases.

In terms of time for gases;

$\frac{\text{Effusion time of gas 1}}{\text{Effusion time of gas 2}}\text{=}\sqrt{\frac{{\text{M}}_{\text{1}}}{{\text{M}}_{\text{2}}}}$