Question

A vessel contains 1 mole of $O_2$ 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 2$T$ has a pressure of ..........$P$

Answer 1

Ideal gas equation $PV=nRT$
For $O_2$ gas: $P=P,V=V,T=T$.
For $He$ gas: $P=P_2,V=V_2=V,T=T_2=2T$.
By comparing them $P_2=2P$.