Question

A student forgot to add the reaction mixture to the round bottomed flask at $27{}^{o}C$ but instead he/she placed the flask on the flame. After a lapse of time, he realized his mistake, and using a pyrometer he found the temperature of the flask was $477{}^{o}C$. What fraction of air would have been expelled out?

Answer 1

The initial temperature $T={27}^{o}C=27+273K=300K$
The final temperature $T^{\prime }={477}^{o}C=477+273K=750K$
The inital volume is V L and the final volume is V' L.
$\frac{V}{V^{\prime }}=\frac{T}{T^{\prime }}$
$\frac{V}{V^{\prime }}=\frac{300}{750}$
$\frac{V}{V^{\prime }}=\frac{2}{5^{\prime }}$
The fraction of air expelled is $1-\frac{V}{V^{\prime }}=1-\frac{2}{5}=\frac{3}{5}$.