Question

Which statement best explains the change that occurs when gas particles move more slowly?
A. The temperature increases because the average kinetic energy decreases.
B. The temperature increases because the average kinetic energy increases.
C. The temperature decreases because the average kinetic energy decreases.
D. The temperature decreases because the average kinetic energy increases.

Answer 1

Answer: C. The temperature decreases because the average kinetic energy decreases.

Explanation:

Kinetic energy is the energy possessed by an object by virtue of its motion.

Average kinetic energy is defined as the average of the kinetic energies of all the particles present in a system. It is given by the equation:

$K=\frac{3RT}{2}$

From above, it is visible that kinetic energy is directly related to the temperature of the system. So, if temperature is more, average kinetic energy of the system is more and thus molecules will move faster.

When temperature is decreased, kinetic energy decreases, and the molecules swill move slowly.

Answer 2

Answer: Option (C) is the correct answer.

Explanation:

Relation between kinetic energy and temperature is as follows.

                $K.E \propto \frac{3}{2}kT$

As, kinetic energy is directly proportional to temperature. So, when there will be increase in temperature then there will also occur increase in kinetic energy of the particles of a substance.

Therefore, when gas particles move more slowly then it means kinetic energy of gas particles is very low. It also implies that temperature is low.

Thus, we can conclude that the statement temperature decreases because the average kinetic energy decreases best explains the change that occurs when gas particles move more slowly.