Four identical rigid cylinders each contain 1.00mol of oxygen gas at 298 K under the indicated conditions:
I. 50 atm, 250 K
II. 50 atm, 500 K
III. 800 atm, 500 K
IV. 5 atm, 250 K
Which cylinder will show the largest positive deviation of molar volume from the ideal-gas prediction, and why?
a) I, because lower temperature amplifies intermolecular attractions.
b) III, because at extremely high pressure the finite size of O2 molecules makes the real molar volume exceed the ideal prediction.
c) II, because higher temperature allows the gas to expand away from ideal behaviour.
d) IV, because low pressure lets the gas expand freely.