As the temperature decreases, which of the following statements is generally true about the kinetic energy of gas particles?

• A. The average kinetic energy of gas particles increases.
• B. The average kinetic energy of gas particles decreases.
• C. The average kinetic energy of gas particles remains unchanged.
• D. The average kinetic energy of gas particles fluctuates randomly.

Answer: (B)

Verified step by step guidance

1. Recall the relationship between temperature and the average kinetic energy of gas particles. The average kinetic energy (KE) of gas particles is directly proportional to the absolute temperature (in Kelvin).
2. Express this relationship mathematically as: \(\text{KE}_{\text{avg}} = \frac{3}{2} k_B T\), where \(k_B\) is the Boltzmann constant and \(T\) is the temperature in Kelvin.
3. Understand that as temperature decreases, the value of \(T\) in the equation decreases, which means the average kinetic energy \(\text{KE}_{\text{avg}}\) also decreases.
4. Recognize that this decrease in kinetic energy means gas particles move more slowly on average at lower temperatures.
5. Conclude that the correct general statement is: 'The average kinetic energy of gas particles decreases as the temperature decreases.'