Practice portal › Kinetic Theory of Gases › Kinetic Energy of Molecules

The gases carbon monoxide (CO) and nitrogen at the same temperature have kinetic energies E₁ and E₂ respectively. Then

Asked in CBSE AIPMT 2000 · Kinetic energy per molecule

Answer: (1) E₁=E₂

Step-by-step solution

Given: CO and N₂ at the same temperature.

Idea: by equipartition the average energy of a molecule depends on its degrees of freedom and the temperature, and on nothing else — not on its mass.

Both molecules are diatomic, so f=5 for each.

Average energy per molecule: f/2k_BT=5/2k_BT for both.

The temperature is the same, so the energies are equal.

E₁=E₂.

Their molar masses happen to be equal too, both 28 g mol⁻¹, but that is not needed: mass never enters the average energy.

Why the other options are wrong

More Kinetic Energy of Molecules questionsAll Kinetic Energy of Molecules questions →

Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.

Practise this with a timer