What is Gay-Lussac's law?
Gay-Lussac’s Law is an ideal gas law where at constant volume, the pressure of an ideal gas is directly proportional to its absolute temperature. In other words, Gay-Lussac's Law states that the pressure of a fixed amount of gas at fixed volume is directly proportional to its temperature in kelvins.
Simplified, this means that if you increase the temperature of a gas, the pressure rises proportionally. Pressure and temperature will both increase or decrease simultaneously as long as the volume is held constant.
The law has a simple mathematical form if the temperature is measured on an absolute scale, such as in kelvins. The Gay-Lussac’s Law is expressed as:
P1T1 = P2T2
Where P1 stands for the initial pressure of the gas, T1 stands for the initial temperature, P2 stands for the final pressure of the gas, and T2 stands for the final temperature.
This law holds true because temperature is a measure of the average kinetic energy of a substance; when the kinetic energy of a gas increases, its particles collide with the container walls more rapidly and exert more pressure.
Take a sample of gas at STP 1 atm and 273 K and double the temperature.
1atm273K=P546K
546atmK273K=P
P = 2 atm
Doubling the temperature, likewise doubled the pressure.