Question Details

The average translational kinetic energy of O₂ (molar mass 32) molecules at a particular temperature is 0.048 eV. The translational kinetic energy of N₂ (molar mass 28) molecules in eV at the same temperature is

Options

A

0.0015

B

0.003

C

0.048

D

0.768

Correct Answer :

0.048

Solution :

The correct option is 0.048.

Step-by-Step Explanation:

According to the kinetic theory of gases, the average translational kinetic energy of a gas molecule is determined solely by its temperature. The formula is expressed as:

Et = 32 kB T

In this equation:


  • kB represents the Boltzmann constant.

  • T represents the absolute temperature of the gas in Kelvin.

Key observations from this physical relation:

1. The average translational kinetic energy is directly proportional to the absolute temperature
T
.

2. The formula does not contain any term representing the mass or molar mass of the gas molecules. Therefore, at a specific temperature, all gas molecules (regardless of their mass) possess the exact same average translational kinetic energy.

Since the nitrogen (N2) molecules are at the same temperature as the oxygen (O2) molecules, their average translational kinetic energy must be identical, completely unaffected by the difference in their molar masses (28 g/mol versus 32 g/mol).

Given that the average translational kinetic energy of O2 is 0.048 eV, the average translational kinetic energy of N2 at the same temperature is also 0.048 eV.

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