For a constant amount of gas at a constant temperature, the product of the pressure and volume of the gas is a constant.
P1V1 = P2V2
For a constant amount of gas at a constant pressure, the volume of the gas is directly proportional to the absolute temperature.
V1/T1 = V2/T2
At a given temperature and pressure, equal volumes of gas contain equal numbers of moles. This is sometimes also known as Avogadro’s law.
Equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.
Thus, 1 mole of any gas (i.e. 6.02 x 1023 gas molecules) at 1 atmosphere pressure and 0°C occupies a volume of approximately 22.4 litres.
Each of these laws is a special case of a more general law. That general law is called the Ideal Gas Law.
P V = n R T
At standard temperature and pressure (commonly abbreviated as STP), the value of the temperature is 0°C (273 K) and the pressure is at 1 atmosphere (760 mmHg or 760 torrs or 1.01 x 105 Nm-2 [pascals] ).
This implies that at STP, 71.0 g of chlorine gas (one mole of chlorine molecules) will occupy a volume of 22.41 litres.
In addition, 44.0 g of carbon dioxide (one mole of carbon dioxide molecules) will also occupy a volume of 22.41 litres at STP.
Dalton's Law of Partial Pressure states that the pressure of a gas mixture is the sum of the partial pressures of the individual components of the gas mixture.
Graham’s Law of diffusion
The rate at which gases diffuse is inversely proportional to the square root of their densities.
Henry's Law states that at a given temperature, the amount of gas dissolved in a solute is directly proportional to the pressure of the gas above the substance.
The pressure required to liquefy a vapour at its critical temperature.
O2 50 bar
N2O 72 bar
CO2 73 bar
The temperature above which a vapour cannot be liquefied by any amount of pressure. Above this temperature, the substance is a gas; below it, a vapour.