A 3.50 mole sample of N₂ in a state defined by T_i = 250.K and V_i = 3.25 L undergoes an isothermal reversible expansion until V_f = 35.5 L. Calculate w assuming a. That the gas is described by the ideal gas law b. That the gas is described by the van der Waals equation of state. What is the percent error in using the ideal gas law instead of the van der Waals equation? The van der Waals parameters for N₂ are listed in Table 7.4.