Chapter 4.2, Problem 23R

To determine

To explain: that the speed of different molecules in the air depend on their masses, although the molecules, on average, have the same kinetic energy.

Explanation of Solution

Introduction:

Kinetic energy is the energy due to motion.

The speed of different molecules in the air depends on their masses, as it is affected by gravitational force. If the mass of the molecule is more, its weight will be more and so the speed of the molecule decreases. Whereas, lighter molecules moves faster as it is not affected by gravity.in an average the kinetic energy of all the molecules is same.

Conclusion:

The speed of a molecule decreases with increase in mass and increases with decrease in mass due to the gravitational force on it.