Question

A helium atom is two times heavier than a hydrogen molecule. At 298 K, the average kinetic energy of a helium atom is

• A. two times that of a hydrogen molecule
• B. four times that of a hydrogen molecule
• C. half that of a hydrogen molecule
• D. same as that of a hydrogen molecule

Answer 1

The correct option is D

same as that of a hydrogen molecule

Kinetic energy of gaseous particles only depend on the temperature as:

K.E. = $\frac{3}{2}kT$

So, both will have the same kinetic energy.