Question

According to the ideal gas law, a 0.9530 mol sample of methane gas in a 1.223 L container at 267.0 K should exert a pressure of 17.07 atm. By what percent does the pressure calculated using the van der Waals' equation differ from the ideal pressure? For CH4 gas, a = 2.253 L2atm/mol2 and b = 4.278×10-2 L/mol. ___ %

Answer 1

Vamanwaal�s Equation of rotate for mole real gas is (P + n^2 a/V^2) (V - nl) = nRT P = nRT/V - nl - n^2 a/V^2 = 0.9530 times 0.082 times 267/1.223 - 0.9530 times 4.278 times 10^-2 - (0.9530) ^2 times 2.253/(1.223) ^2 = 20.86/1.223 - 0.04076 - 2.0461/1.4957 = 20.86/1.18224 - 2.0461/1.4957 = 17.644 - 1.3679 = 16.2761 atm therefore Defter of pressure = (17.07 - 16.2761) = 0.7939 atm % of pressure defter from the ideal pressure = 0.7939/17.07 times 100% = 4.65%