A vessel contains 1 mole of O2 gas (molar mass 32) at a temperature T. The pressure of the gas is P. An identical vessel containing one mole of He gas (molar mass 4) at a temperature 2T has a pressure of
2P
For a gas, PV = nRT. Hence
(P)O2 = (1mole)RTV
and (P)He = (1mole)R(2T)V
∴ (P)He(P)O2 = 2 or (P)He = 2(P)O2