Comment:  The Dangers of Extrapolation  (Rene Magritte, "The Human Condition," 1935.)

The ideal gas law becomes less accurate as we extrapolate to higher pressures!  Judgment is required to know how far is can be applied before deviations are meaningful to your situation.

3-33. No. 9

Acetonitrile, C2H3N, is stored at a temperature of 550 F and a pressure of 4500 psia in a high pressure vessel (A) with a capacity of 0.2 cubic feet. For safety, the 0.2 ft3 vessel is contained in a second pressure vessel. The volume of the second vessel (B) is 2 ft3 (exclusive of the volume occupied by vessel A which it surrounds). This volume is filled with inert nitrogen at 10 atmospheres pressure. The entire assembly is maintained at 550°F. If the inner tank ruptures, what is the final pressure? The critical data and a diagram of the tanks are as follows:

Tc K Pc atm

N₂ 126.2 33.5

C₂H₃N 548.0 47.7