If 1.00 \rm mol of argon is placed in a 0.500-\rm L container at 20.0\, ^{\circ}C, what is the difference between the ideal pressure (as predicted by the ideal gas law) and the real pressure (as predicted by the van der Waals equation)?
For argon, a = 1.345 \;\rm (L^2\cdot atm)/mol^2 and b = 0.03219\; \rm L/mol.