Aballoon contains 30.0 l of helium gas at 103 kpa. what is the volume of the helium when the balloon rises to an altitude where the pressure is only 25.0 kpa?

                V₂  =  123.6 L

Explanation:

According to Boyle's law pressure and volume of a gas are inversely related if amount and temperature are kept constant. For the initial and final states the gas law is given as,

                                                P₁ V₁  =  P₂ V₂      (1)
Data Given;
                   P₁  =  103 kPa

                   V₁  =  30 L

                   P₂  =  25 kPa

                   V₂  =  ?

Solution:

Solving equation 1 for V₂,

                                        V₂  =  P₁ V₁ / P₂

Putting values,
                                        V₂  =  (103 kPa × 30 L) ÷ 25 kPa

                                        V₂  =  123.6 L

Result:
           As the pressure is decreased from 103 kPa to 25 kPa, therefore, volume has increased from 30 L to 123.6 L.