Question

A balloon has certain volume at sea level. At what pressure (in kPa) will its volume be increased by 40% if the temperature is kept constant?

Answer 1

Given: P₁ = Initial pressure = 101.325 kPa (∵ The pressure at sea level = 101.325 kPa)

V₁ = Initial volume at sea level = 100 dm³ (assumption)

V₂ = Final volume = (100 + 40) = 140 dm³

To find: P₂ = Final pressure

Formula: P₁ V₁ = P₂ V₂ (at constant n and T) 

Calculation: According to Boyle’s law

P₁ V₁ = P₂ V₂ (at constant n and T)

P₂ = \(\frac{P_1V_1}{V_2}\)

∴ P₂ = \(\frac{101.325\times 100}{140}\) = 72.375 kPa

The pressure at which volume of the given balloon will be increased by 40% at a given temperature is 72.375 kPa.