Question

Which of the following gas molecules have the greatest average molecular speed at 100${}^o$$C$?

• A. Carbon dioxide
• B. Chlorine
• C. Nitrogen
• D. Oxygen

Answer 1

Answer: (C)

Nitrogen

Average velocity of the gas molecule has the formula : $U_{avg}=\sqrt{\frac{8RT}{\pi M}}$

R = Gas constant

T = temperature

M = molecular mass of the molecule

So, $U_{avg}\propto \frac{1}{\sqrt{M}}$ at constant temperature.

Nitrogen has the lowest molecular mass among them, so it has higher $U_{avg}$ value.