Question

What would be the pressure (in atm) of $O_2$ in the following experiment? A collapsed bag of 30 litre capacity is partially blown up by the addition of 10 litre of $N_2$ at 0.965atm at 298K. Subsequentally enough $O_2$ is pumped into bag, so that at 298K and external pressure of 0.990atm, the bag contains full 30litre.
Write numerical value (upto 2 digit only) after decimal point only ( as for 0.19, write 19)

Answer 1

Initial condition, $P_{N_2}=0.965atm,V=10litre,T=298K$

Now $O_2$ is introduced to expand the bag fully to 30 litre,$N_2$ also occupy 30litre at 298K

For $N_2$ alone new pressure is to be calculated by

$P_1{V}_1=P_2{V}_2;0.965\ast 10=P_{N_2}\ast 30$

$P_{N_2}=0.322$atm (at 30litre volume)

$P_{O_2}=P_T-P_{N_2}=0.990-0.32=0.668$ atm

So, answer is 66.