Concepts Of Physics MCQ Edition [Volume 2]PhysicsKinetic Theory of Gases
Suppose a collision occurs between an oxygen molecule and a hydrogen molecule in a mixture of oxygen and hydrogen maintained at room temperature. Which of the following outcomes are possible?
Options
- AThe kinetic energies of both molecules decrease.
- BThe kinetic energy of the oxygen molecule increases while that of the hydrogen molecule decreases.
- CThe kinetic energies of both molecules increase.
- DThe kinetic energy of the hydrogen molecule increases while that of the oxygen molecule decreases.
Correct answer
D. The kinetic energy of the hydrogen molecule increases while that of the oxygen molecule decreases.
Step-by-step solution
During a collision between an oxygen molecule and a hydrogen molecule, the total energy of the two-molecule system is conserved. The total energy consists of translational kinetic energy and internal energy (rotational and vibrational energies). If the collision is elastic, there is no change in the internal energy. The total translational kinetic energy remains constant. Therefore, the kinetic energy of one molecule must increase while that of the other decreases. This makes the second and fourth outcomes possible