$1.$ A gas mixture is stored at $20$ MPa and $300$ K$,$ containing $3$ kmol of gas A and

$8$ kmol of gas B$.$

$($a$)$ Estimate the tank volume using the Ideal Gas Law.

$(3$ marks$)$

$($b$)$ Estimate the tank volume using the generalised compressibility chart $($Figure Q$1).$ The critical properties of the components are given in Table Q$1.$

$(10$ marks$)$

$($c$)$ Calculate the molar volume of the gas mixture at the storage conditions