A gas 'X' at -33°C is heated to 127°C at constant pressure. Calculate the percentage increase in the volume of the gas.

V₁ = Initial volume of the gas = V cc
T₁ = Initial temperature of the gas = -33°C = -33 + 273 = 240 K

T₂ = Final temperature of the gas = 127°C = 127 + 273 = 400 K
V₂ = Final volume of the gas = ?

By Charles's Law:

$\dfrac{\text{V}$1}{\text{T}1} = \dfrac{\text{V}2}{\text{T}2}

Substituting the values :

$\dfrac{\text{V}}{240} = \dfrac{\text{V}$2}{400} \\[1em] \text{V}2 = \dfrac{400 \times \text{V}}{240} \\[1em] \text{V}_2 = \dfrac{5\times \text{V}}{3}

Increase in vol. = $\dfrac{5\text{V}}{3}$ - V = $\dfrac{2\text{V}}{3}$

Percentage increase in vol. = $\dfrac{\text{Increase}}{\text{Original}}$ x 100 = $\dfrac{2\text{V}}{3\text{V}}$ x 100 = 66.67%

Therefore, percentage increase in the volume of the gas = 66.67 %