Question

Two identical vessels contain helium and hydrogen at same temperature, then

• A. Average kinetic energy per mole of hydrogen = Average kinetic energy per mole of helium
• B. Average translational kinetic energy per mole of hydrogen = Average translational kinetic energy per mole of helium
• C. Average kinetic energy per mole of hydrogen $=\frac{3}{5}$ average kinetic energy per mole of helium
• D. Average kinetic energy per mole of hydrogen $=\frac{5}{3}$ average kinetic energy per mole of helium

Answer 1

Answer: (B), (D)

The correct options are
B

Average translational kinetic energy per mole of hydrogen = Average translational kinetic energy per mole of helium

D

Average kinetic energy per mole of hydrogen $=\frac{5}{3}$ average kinetic energy per mole of helium

$K_T=\frac{3}{2}\text{RT}$ for one mole of any gas. Here, $K_T=$ average translational kinetic energy

$K_{\text{Total}}=\frac{f}{2}\text{RT}$ for one mole

Here, f = total degrees of freedom

= 3 for He (monoatomic)

= 5 for $H_2$ (diatomic)