Question

The average translational kinetic energy of \( O_2 \) (molar mass 32) molecules at a particular temperature is 0.048 eV. The translational kinetic energy of \( N_2 \) (molar mass 28) molecules in eV at the same temperature is:

• A. 0.0015 eV
• B. 0.003 eV
• C. 0.048 eV
• D. 0.768 eV

Hint:

The average kinetic energy per molecule depends only on temperature and is independent of the molecular mass.

Answer 1

The Correct Option is C

Step 1: Kinetic energy for ideal gases.
The average kinetic energy of a molecule in an ideal gas is given by: \[ E_k = \frac{3}{2} k_B T \] where \( k_B \) is the Boltzmann constant and \( T \) is the temperature. Since both gases are at the same temperature, the average kinetic energy per molecule will be the same for both gases. Hence, the correct answer is (3).