Question

Two flasks of equal volume have been joined by a narrow tube of negligible volume. Initially, both flasks are at 300K containing 0.6 mole of $O_2$ at 0.5 atm pressure. one of the flasks is placed in the thermostat of 600K. FInd the number of mole of $O_2$ gas in each flask.

• A. 0.5mol and 0.3 mol
• B. 0.5mol and 0.2 mol
  
• C. 0.4mol and 0.2 mol
  
• D. 0.6mol and 0.3 mol
  

Answer 1

Answer: (C)

0.4mol and 0.2 mol

$0.5V_1=0.6R\times 300$

$V=360R$

in 2nd case the pressure will be same for both flask and sum of moles is 0.6

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-

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

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