A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and xenon. c. The molecules of which gas have the greater average kinetic energy?

Key Concepts

Kinetic Molecular Theory

The Kinetic Molecular Theory explains the behavior of gases in terms of particles in constant motion. It states that the average kinetic energy of gas molecules is directly proportional to the temperature of the gas in Kelvin. This means that at the same temperature, all gases have the same average kinetic energy, regardless of their molecular mass.

Temperature and Kinetic Energy

Temperature is a measure of the average kinetic energy of the particles in a substance. In the context of gases, if two gases are at the same temperature, their average kinetic energies will be equal. Therefore, the average kinetic energy of nitrogen and xenon in the flask will be the same since they are both at room temperature.

Molecular Mass and Speed

While the average kinetic energy of gas molecules is the same at a given temperature, the speed of the molecules varies with their mass. Lighter molecules, like nitrogen (N2), move faster than heavier molecules, like xenon (Xe). This difference in speed does not affect the average kinetic energy but is important for understanding the behavior of gases in terms of diffusion and effusion.