Question

$4gm$ Hydrogen is mixed with $11.2$ litre of $He$ at S.T.P. in a container of volume $20$ litre. If the final temperature is $300K$, find the pressure.

Answer 1

$4gmHydrogen=2moles$ Hydrogen
and $11.2l.He$ at S.T.P. $=\frac{1}{2}$ mole of $He$
$P=P_H+P_{He}=(n_H+n_{He})\frac{RT}{V}=(2+\frac{1}{2})\frac{8.3\times \left(300K\right)}{(2-\times {10}^{-3})m^3}=3.11\times {10}^{5}N/m^2$.