Concepts Of Physics MCQ Edition [Volume 2]PhysicsKinetic Theory of Gases
Which of the following determines the average momentum of a molecule in a sample of an ideal gas?
Options
- AThe number of moles in the sample
- BThe volume of the gas
- CThe temperature of the gas
- DIt is always zero, thus independent of these parameters
Correct answer
D. It is always zero, thus independent of these parameters
Step-by-step solution
Momentum is a vector quantity given by p = m v . In an ideal gas, the molecules are in continuous, random motion in all possible directions. For every molecule moving with a certain velocity v , there is, on average, another molecule moving with velocity - v . As a result, the average velocity of the molecules in a stationary container is zero, i.e., v = 0 . Therefore, the average momentum of a molecule is p = m v = 0 . Since it is always zero, it is independent of the number of moles, volume, and temperature of th