The study of the physical properties of gases by several scientists between the 16th and 19th centuries resulted in the formulation of gas laws. These laws provide a relationship between the volume occupied by a gas, the pressure exerted by a gaseous substance on the walls of its container, the amount of gaseous substance, and the absolute temperature of the gas. These laws were critical in the development of the ideal gas law.

**Four Gas laws**

The four gas laws and the relationships they provide are:

- Boyle’s law – the relationship between the pressure exerted by a gaseous substance on the walls of its container and the volume occupied by the gas.
- Charles’ law – the relationship between the absolute temperature of the gas and the volume occupied by the gas.
- Gay-Lussac’s law – the relationship between the pressure exerted by a gaseous substance on the walls of its container and the absolute temperature of the gas.
- Avogadro’s law – the relationship between the volume occupied by a gas and the amount of gaseous substance.

### Boyle’s law

According to Boyle’s law, the volume of the gas is inversely related to pressure when the amount of gas is fixed at a constant temperature. Mathematical representation of the law is given as follows:

P∝1V

PV = constant

P_{1}V_{1} = P_{2}V_{2} = P_{3}V_{3} = constant

Where,

P is the pressure of a gas

V is the volume of gas

### Charles’s Law

According to Charles’s law, the volume of the gas with a fixed mass is directly proportional to the temperature. Mathematical representation of the law is given as follows:

V ∝ T

Where,

T is the temperature of a gas

V is the volume of gas

### Gay-Lussac’s Law

According to Gay-Lussac’s law, when the volume of the gas is constant, the pressure of a given mass of gas varies directly with the absolute temperature of the gas. Mathematical representation of the law is given as follows:

P_{1}T_{1}=P_{2}T_{2}

Where,

T1 is the initial temperature

P1 is the initial pressure

T2 is the final temperature

P2 is the final pressure

### Avogadro’s Law

According to Avogadro’s law, when the pressure and temperature of the given gas are constant, then the number of moles and the volume of the gas are in a direct relationship. Mathematical representation of the law is given as follows

V ∝ n or Vn=k

Where,

V is the volume of the gas

n is the number of moles

k is the proportionality constant