What is the law that relates the variables of pressure, volume, and temperature?

The law that relates the variables of pressure, volume, and temperature in a more comprehensive way is the Combined Gas Law. This law combines Boyle's Law, which describes the relationship between pressure and volume at a constant temperature, and Charles's Law, which addresses the relationship between volume and temperature at a constant pressure. The Combined Gas Law can be expressed mathematically as P1V1/T1 = P2V2/T2, where P, V, and T represent the pressure, volume, and temperature of a gas, respectively.

This law is particularly useful because it allows you to analyze changes in a gas's state when temperature, pressure, and volume are all varying, making it a more versatile tool than the individual laws it encompasses. In practical situations, when gas undergoes changes in these three variables, the Combined Gas Law provides a complete picture of how these changes affect the behavior of the gas.

The other laws, while important, do not collectively account for the interdependence of all three variables as succinctly as the Combined Gas Law does.