According to the kinetic molecular theory, what happens to the motion of gas particles when a gas is heated?

• A. The gas particles decrease in size and mass.
• B. The gas particles move faster as their average kinetic energy increases.
• C. The gas particles move slower as their average kinetic energy decreases.
• D. The gas particles stop moving and settle at the bottom of the container.

Answer: (B)

Verified step by step guidance

1. Recall the kinetic molecular theory, which explains the behavior of gas particles in terms of their motion and energy.
2. Understand that the average kinetic energy of gas particles is directly proportional to the temperature of the gas, expressed as \(KE_{avg} = \frac{3}{2} k_B T\), where \(k_B\) is Boltzmann's constant and \(T\) is the temperature in kelvins.
3. Recognize that when a gas is heated, its temperature increases, which means the average kinetic energy of the gas particles increases.
4. Since kinetic energy is related to the speed of the particles by \(KE = \frac{1}{2} m v^2\), an increase in kinetic energy implies that the particles move faster.
5. Conclude that heating a gas causes its particles to move faster due to the increase in their average kinetic energy, rather than changing their size, mass, or causing them to stop moving.