Question

An open vessel at ${27}^{o}C$ is heated until three fourths mass of the air in it has been expelled. Neglecting the expansion of the vessel, find the temperature to which the vessel has been heated?

Answer 1

Initial mass of gas at ${27}^{o}C$ be $n=n_1$

on heating $\frac{3}{4}$ mole of air expells at temperature T

$\therefore$ moles of air left at $T=n-\frac{3n}{4}=\frac{n}{4}$

Under initial condition of P and V

$n_1{T}_1=n_2{T}_2$

$n\times 300=\frac{n}{4}\times T$

$T=1200K={926.85}^{o}C$