Question

which two of the following statements correctly describe the relationship between temperature and the kinetic energy of particles in a substance?
a. as temperature increases, the average kinetic energy of particles increases.
b. as temperature decreases, particles move faster and have more kinetic energy.
c. the kinetic energy of particles is directly proportional to the temperature of the substance.
d. temperature has no effect on the kinetic energy of particles in a substance.
e. as temperature increases, particles become completely stationary.

Explanation:

• Option A: According to the kinetic - molecular theory, temperature is a measure of the average kinetic energy of the particles in a substance. So, as temperature increases, the average kinetic energy of particles increases.
• Option B: When temperature decreases, particles move slower and have less kinetic energy, not faster. So this option is wrong.
• Option C: The kinetic energy of particles is directly proportional to the temperature of the substance (in Kelvin). This is a fundamental concept from the kinetic - molecular theory.
• Option D: Temperature has a significant effect on the kinetic energy of particles. As shown in options A and C, this option is incorrect.
• Option E: As temperature increases, particles move faster, not become stationary. When temperature approaches absolute zero (\(T = 0\space K\)), particles have the minimum kinetic energy but not at higher temperatures.

Answer:

A. As temperature increases, the average kinetic energy of particles increases; C. The kinetic energy of particles is directly proportional to the temperature of the substance.