According to the kinetic molecular theory, what happens to gas molecules when their kinetic energy decreases?

• A. The molecules undergo chemical reactions more easily.
• B. The molecules move more slowly and collide less frequently.
• C. The molecules increase in size.
• D. The molecules move more rapidly and collide more frequently.

Answer: (B)

Verified step by step guidance

1. Recall that the kinetic molecular theory describes the behavior of gas molecules in terms of their motion and energy.
2. Understand that the kinetic energy of gas molecules is directly related to their temperature; when kinetic energy decreases, the temperature decreases.
3. Recognize that kinetic energy is proportional to the speed of the molecules, so a decrease in kinetic energy means the molecules move more slowly.
4. Since the molecules move more slowly, they collide less frequently because their motion is reduced.
5. Conclude that when the kinetic energy decreases, gas molecules move more slowly and collide less frequently, which matches the correct answer.