Answer (a), (b) and (c). (a) The density of a gaseous compound was found to be 1.23 g/L at 330 K and 20 kPa. What is the molar mass of the compound? (b) Define the compression factor, and use the plot of compression factor for nitrogen gas at different temperatures at left to discuss the formulation of the van der Waals equation, below, from the perfect gas equation, identifying the terms in the equation. P = nRT / (V - nb) - a(n/V)^2 (c) Calculate the pressure exerted by 1.0 mol of N2 gas at 300 K in 0.1 L vessel behaving as (i) a perfect gas and (ii) a van der Waals gas, where a = 137.0 L^2 mol^-2 kPa and b = 0.00387 L mol^-1. Comment on how reliable the perfect gas law is under these conditions.