There are three gas laws. The laws relate the way the pressure, volume and temperature of a fixed mass of gas change together. In words they state:

The pressure of a fixed mass of gas is proportional to the temperature if the volume is kept constant. This is called the pressure law. It is usually stated in the formwhereandare the initial pressure and temperature andandare the final pressure and temperature respectively.

The pressure of a fixed mass of gas is inversely proportional to the volume if the temperature is kept constant. This is called Boyle's law. It is usually stated in the formwhere andare the initial pressure and volume andandare the final pressure and volume respectively.

The volume of a fixed mass of gas is proportional to the temperature if the pressure is kept constant. This is called Charle's law. It is usually stated in the formwhereandare the initial volume and temperature andandare the final volume and temperature respectively.

Example: A gas at a temperature of 200 ° K has a pressure of 40,000 Pa. Find the pressure when the temperature increases to 350 ° K if the volume is kept constant.

Example: A gas occupies a volume of 3.4 m ^{3 } has a pressure of 80,000 Pa. Find the pressure when the volume decreases to 2 m ^{3 } if the temperature is kept constant.

Example: A gas at a temperature of 200 ° K occupies a volume of 3.2 m ^{3 }. Find the volume when the temperature increases to 500 ° K if the pressure is kept constant.