What effect does a decrease in temperature have on the pressure of a gas?

A decrease in temperature leads to a decrease in the pressure of a gas because of the relationship defined by the ideal gas law, which is expressed as PV = nRT. In this equation, P represents pressure, V represents volume, n is the number of moles of gas, R is the ideal gas constant, and T is the temperature in Kelvin.

When the temperature (T) decreases, and if the volume (V) of the gas remains constant, the pressure (P) must also decrease to maintain the equality outlined by this equation. This occurs because lower temperatures result in reduced kinetic energy among gas molecules. Since the kinetic energy is responsible for the motion and collisions of gas particles with the walls of the container, a reduction in temperature leads to fewer collisions and less force exerted on the walls of the containment. Hence, the overall pressure decreases.

This concept can be observed through practical examples such as when a gas is cooled in a rigid container, and the pressure will fall as the temperature falls. Understanding this relationship is crucial for applications in thermodynamics and gas laws, as it illustrates one of the fundamental behaviors of gases in response to changes in temperature.