Question

U20 9. Using the van der Waals equation, calculate the pressure for a 1.25 mol sample of xenon contained in a volume of 1.000L at 75°C: a = 4.194 L'atm/mol and b = 0.05105 L/mol for Xe. Compare these results to that predicted by the ideal gas law.

Answer 1

No of moles of the Xe gas, n 1.25 mol Temperature, T = 75°C+273 348 K Gas constant, R = 0.0821 L.atm.K^mol"1 Volume of the gas, V 1.000 L According to ideal gas equati on, PV = nRT nRT Pressure of the Xe gas, P = (1.25 mol)0.0821 L. atm.Kmol)(348K) 1.000 L = 35,7 atm b) No of moles of the Xe gas, = 1.25 mol Temperature, T = 75°C +273 348 K Gas constant, R = 0.0821 L.atm.K^mol1 Volume of the gas, V = 1.00 L Vanderwalls constants for Xe a 4.194 L2.atm/mol2 b 0.05105 L/mol According to Van derwalls equati on,P+ - nb) = nRT nRT an2 P = V-nb 1.25 mol x0.0821 L. atm K'mol *348K (1.00 L 1.25 mol x0.05105 L/mol) 4.194 L2 atm/m ol2 (1.25 mol) (1.00 L) 1.25 mol x0.0821 L.atm K molx 348K 0.9361875 L 4.194 L2 atm/m ol2 (1.25 mol) (1.00 L) = 38.1 atm -6,6 atm = 31.5 atm Pide Pn de Wak 100% % of ideal pres sure 2 35.7 atm 31.5atm 35.7 atm +31.5 atm -x100% 4.2 atm x100% 33.6 atm = 12.5%