Chapter-3

Boyle’s Law:

Introduction:  Robert Boyle in 1662 gave a relationship between volume and pressure of a fixed amount gas at constant temperature. The law is known after his name as Boyle’s law.

Statement 1:  The volume of a given mass of a gas is inversely proportional to its pressure at constant temperature.

Mathematically

                         V α     1                      (1)

P

To convert proportionality into equality a constant is introduced so when constant ‘K’  is introduced to the above relation the equation will be

                        V =      K                     where K is proportionality constant

P

 OR

PV = K                        (2)

Statement 2: On the basis of above equation 2 the Boyle’s law is also defined as The product of pressure and volume of a given mass of a gas is always constant at constant temperature.

Let V1 be the volume of a gas having pressure P1 at certain temperature. If the pressure of that gas is changed to P2 at same temperature then the volume will change to V2 and equation 2 will be

P1V1 = P2V2  (3) at constant temperature and amount of gas