# Facts about Behaviour of Gases

All gases containing equal amount of substances occupy the same volume at the same temperature and pressure

Gas Laws

Boyle's Law: The pressure of a fixed amount of a gas varies inversely with the volume if the temperature is maintained constant.

Charle's Law: The volume of a fixed amount of a gas varies directly with its absolute temperature at constant pressure.

Gay-Lussac's Law: At constant volume, the pressure of given mass of gas is directly proportional to the temperature in Kelvin.

Avogadro Law: It states that at a given temperature and pressure the volume of a gas is directly proportional to the amount of gas.

Ideal Gas Equation
Boyles law, V T (n, t constant) ------------- (1)

Charles law, V T (n, P constant) ------------- (2)

Avogadro's law, V T (P, T constant) ------------- (3)

Combining the three

V 1/P x T x n
or V = a constant x nT/P

This constant is known as universal gas constant and is denoted as 'R'

Then, V – R x n x T/P

PV= n x R x T
i.e. PV = nRT

This equation is called Ideal gas equation.