At constant volume, the absolute pressure of a gas varies directly with which of the following?

The relationship between the absolute pressure of a gas and its absolute temperature at constant volume is well articulated through Gay-Lussac's Law. This law states that for a given amount of gas at a fixed volume, the pressure is directly proportional to the absolute temperature.

When the temperature of the gas increases, the kinetic energy of the gas molecules also increases, leading to more frequent and forceful collisions with the walls of the container, thereby increasing the pressure. Conversely, if the temperature decreases, the pressure drops as the kinetic energy of the molecules is reduced, resulting in fewer and less intense collisions.

This direct relationship holds true as long as the volume remains constant, meaning any change in temperature directly influences the pressure. Thus, when examining the options, absolute temperature is indeed the correct factor that varies directly with absolute pressure under the specified condition.