Question

Two flask of equal volume have been joined by a narrow tube of negligible volume. Initially both flasks are at $300K$ containing $0.60$ mole of $O_2$ gas at $0.5atm$ pressure. One of the flask is then placed in a thermostat at $600K$. Calculate final pressure and the number of $O_2$ gas in each flask.

Answer 1

Ideal gas law- $PV=nRT$

$P_{1}V=n_{1}RT$ [Volume is constant]

$0.5V_1=0.6R\times 300$

$V=360R$

in 2nd case the pressure will be same for both flask and sum of moles is .6

Flask-1

$P\times 360R=n_{1}R\times 300$

$n_1=1.2P$

Flask-2

$P\times 360R=n_{2}R\times 600$

$n_2=0.6P$

$n_1+n_2=0.6$

$1.2P+0.6P=0.6$

$1.8P=0.6$

Final pressure-

$P=\frac{1}{3}$

Number of moles of oxygen in flasks-

$n_1=1.2\times \frac{1}{3}=0.4$

$n_2=0.6\times \frac{1}{3}=0.2$