Gas Laws

Theory

Boyle’s Law: Volume and Pressure:

This law illustrates inverse relationship between volume and pressure—an increase in one results in a decrease in the other, keeping temperature and number of moles constant.

Boyle’s law follows from the idea that pressure results from the collisions of the gas particles with the walls of their container. If the volume of a gas sample is decreased, the same number of gas particles is crowded into a smaller volume, resulting in more collisions with the walls and therefore an increase in the pressure.
PV = constant
For two different sets of conditions, P₁V₁ = constant = P₂V₂
or, P₁V₁ = P₂V₂
where and are the initial pressure and volume of the gas and and are the final pressure and volume.

Charles’s Law: Volume and Temperature:

Charles showed that volume and temperature are linearly related, keeping pressure and number of moles constant.

or

When the temperature of a gas sample is increased, the gas particles move faster; collisions with the walls are more frequent, and the force exerted with each collision is greater.
For two different measurements, 

where and are the initial volume and temperature of the gas and and are the final volume and temperature. The temperatures must always be expressed in kelvins (K).

Avogadro’s Law: Volume and Amount (in Moles):

According to this law, there is direct proportionality of volume and number of moles, as long as the pressure and temperature of the gas are constant.

or
 where and are the initial volume and number of moles of the gas and and are the final volume and number of moles.