Question

A vessel contains a mixture of one mole of oxygen and two ***** of nitrogen at 300 K. The ratio of the average rotational kinetic energy per O2 molecule to that per N2 molecule is

(a) 1 : 1

(b) 1 : 2

(c) 2 : 1

(d) Depends on the moments of inertia of the two molecules

Answer 1

Correct Option (a) 1 : 1

Explanation:

Kinetic energy per degree of freedom = 1/2 kT

As diatomic gas possess two degree of freedom for rotational motion therefore rotational

K.E. = 2(1/2kT) = kT

In the problem both gases (oxygen and nitrogen) are diatomic and have same temperature (300 K) therefore ratio of average rotational kinetic energy will be equal to one.