What would be the final pressure of O2 in following experiment? A collapsed polethylene bag of 30 litre capacity is partially blown up by the addition of 10 litres of N2 at 0.965 atm at 298 K. Subsequently enough O2 is pumped into bag so that at 298 K and external pressure of 0.990 atm, the bag contains 30 litres N2.

Q: What would be the final pressure of O2 in following experiment? A collapsed polethylene bag of 30 litre capacity is partially blown up by the addition of 10 litres of N2 at 0.965 atm at 298 K. Subsequently enough O2 is pumped into bag so that at 298 K and external pressure of 0.990 atm, the bag contains 30 litres N2.

Solution: Given pressure of N2 = 0.965 atm

Volume of N2 = 10 litre. Temperature of N2 = 298 K

For N2 when bag is fully expanded,

Volume of N2 (alone) = 30 litre at 298 K

P1V1 = P2 V2

0.965 × 10 = P2 × 30

PN2 (alone) in 30 litre bag at 298 K = 0.322 atm

Now PM = PO2 + PN2

0.990 = PO2 + 0.332

PO2 = 0.668 atm