Answer to Question #324128 in General Chemistry for Zeinab

Question

33. Consider the following reaction : CO(g)+2H 2 (g) CH 3 OH(liq.) Given : Delta f G^ (CO)=-137 kJ.mol^ -1 , Delta f G^ (CH 3 OH)=-166 kJ.mol^ -1 Calculate Delta_{r}*G at 25 degrees * C for the following pressures : P(CO) = 5 atm and P(H_{2}) = 3atm .

Answer 1

∆G⁰_rxn = $\Sigma$∆G_prod - $\Sigma$∆G_react = ∆G(CH₃OH) - (∆G(CO) + 2×∆G(H₂)) = -166 kJ/mol - (-137 kJ/mol + 2×0 kJ/mol) = -29 kJ

∆G_rxn = ∆G⁰_rxn + RTlnQ

Q = 1 / (p_CO × p²_H2) = 1 / (5 atm × (3 atm)²) = 0.022

∆G_rxn = -29 kJ + (0.00831 kJ/mol K) × (298 K) × ln(0.022) = -38.45 kJ