The temperature of a gas sample in a rigid container is reduced. The pressure the gas exerts on the container walls decreases because
A) its molecules are in contact with the walls for briefer intervals.
B) its molecular masses decrease.
C) its molecules have lower average speeds and so strike the walls less often with less momentum.
D) its molecules lose less energy each time they strike the walls.

Question

Quizplus · Accepted Answer

As the temperature of the gas sample is reduced, the average speed of the gas molecules also decreases. This means that the molecules strike the walls of the container less often and with less momentum, resulting in a decrease in the pressure the gas exerts on the container walls. Therefore, choice C is the best answer.

The Temperature of a Gas Sample in a Rigid Container