You are picking up your weekly supply of krypton gas from your local supplier, and you notice that the cylinder pressure gauge reads 149 bar, i.e. 150 bar absolute, and the cylinder is warm to the touch (40C). You mention this to the supplier, who realizes that it has not cooled down from its recent compression. He agrees to give you a discount, because there would be more gas in the same volume at the same pressure at ambient temperature, say 20C.

a) Calculate the percentage discount to which you would be entitled.

b) After the gas cylinder is left to stand overnight it cools to 20C. What would the pressure in the cylinder be after it cools off this way?

Use the approach involving the generalized second virial coefficient.