Which gas law states that the pressure of a given mass of gas is directly proportional to its temperature?

The gas law that states the pressure of a given mass of gas is directly proportional to its absolute temperature is Gay-Lussac's Law. This relationship can be expressed mathematically as ( P \propto T ) when the volume of the gas is kept constant. This means that if the temperature of the gas increases, the pressure increases, provided that the amount of gas and the volume do not change.

This principle applies under several conditions and is fundamental in understanding how gases behave in response to temperature changes. For instance, if a gas is heated, the increase in kinetic energy of the gas molecules leads to more frequent and forceful collisions with the walls of the container, thus increasing the pressure.

In contrast, Boyle's Law relates pressure and volume at a constant temperature, Charles's Law connects volume and temperature at a constant pressure, and Avogadro's Law relates volume and amount of gas at a constant temperature and pressure. Each of these laws deals with different relationships among pressure, volume, temperature, and the amount of gas, defining their specific applicability in various scenarios.