Question

A balloon is inflated with helium gas at room temperature of 25 °C and at 1 bar pressure when its initial volume is 2.27L and allowed to rise in air. As it rises in the air external pressure decreases and the volume of the gas increases till finally it bursts when external pressure is 0.3bar. What is the limit at which volume of the balloon can stay inflated ?

Answer 1

Given : 

P₁ = Initial pressure = 1 bar 

V₁ = Initial volume = 2.27 L 

P₂ = Final pressure = 0.3 bar 

To find :

V₂ = Final volume 

Formula : 

P₁V₁ = P₂V₂ (at constant n and T) 

Calculation :

According to Boyle’s law,

P₁V₁ = P₂V₂ (at constant n and T) 

∴ V₂ = \(\frac{P_1V_1}{P_2}\)

= \(\frac{1\times 2.27}{0.3}\) 

= 7.566667 L ≈ 7.567 L

∴ The balloon can stay inflated below the volume of 7.567 L.