SAT Subject Physics Practice Question 671: Answer and Explanation
7. A container holds 1 mole of an ideal gas. If the temperature of the gas is held constant and the volume of the gas is halved, the pressure of the gas will double. This happens because
A. the gas particles have gained energy.
B. the gas particles collide with one another more often.
C. the gas particles move more slowly.
D. the gas particles collide with the container walls less often.
E. the gas particles collide with the container walls more often.
Correct Answer: E
The correct answer is (E). Pressure is the measure of the rate at which the gas particles collide with the sides of the containers. The more often the gas particles collide with the container walls, the higher the pressure.