Chemistry - Ideal Gas Question with Solution | TestHub

Using the ideal gas law, $PV=nRT$. For an open flask, pressure is constant and volume is fixed, so $n\propto \frac{1}{T}$.

Initial temperature $T_1=300K$, final temperature $T_2=500K$.

So, $\frac{n_2}{n_1}=\frac{T_1}{T_2}=\frac{300}{500}=\frac{3}{5}$.

Remaining gas = $\frac{3}{5}$ of initial, so escaped gas = $1-\frac{3}{5}=\frac{2}{5}$.

Percentage escaped = $\left(\frac{2}{5}\right)\times 100=40\%$.