Question

Helium gas diffuses 4 times as fast as an unknown gas. What is relative molecular mass of the gas​

Answer 1

The relative molecular mass of the gas​ : 64 g/mol

Further explanation

Given

Helium rate = 4x an unknown gas

Required

The relative molecular mass of the gas​

Solution

Graham's Law

$\tt \dfrac{r_1}{r_2}=\sqrt{\dfrac{M_2}{M_1} }$

r₁=4 x r₂

r₁ = Helium rate

r₂ = unknown gas rate

M₁= relative molecular mass of Helium = 4 g/mol

M₂ = relative molecular mass of the gas​

Input the value :

$\tt \dfrac{4r_2}{r_2}=\sqrt{\dfrac{M_2}{4} }\\\\16=\dfrac{M_2}{4}\\\\M_2=64~g/mol$