Question

The average molecular speed in a sample of CH4 gas at a certain temperature is 659 m/s.

The average molecular speed in a sample of H2 gas is ____________
m/s at the same temperature.

Answer 1

The average molecular speed formula is

$v= \sqrt{\frac{8RT}{\pi M}}$ where v is inversely proportional to M ^1/2

^Therefore,

$\dfrac{V1}{V2}$ = $[\dfrac{M2}{M1}]^1/2$

$\dfrac{659}{V2}=$ $[\dfrac{2}{16}]^1/2$

$V2=\dfrac{659}{0.015625}$

$V2=42176 m/s$