(a) The total gross sales of N2 is 30,000 units. Take the volume of the cylinder to be 43 L, the pressure to be 12,400kPa, and the cost to be $6.1/kg. Compare your results (using Redlich-Kwong E.O.S.) to that you wound obtain using the ideal gas model.
(b) Repeat for 30,000 units of O2 at 15,000kPa and $9/kg