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SECTION F Chemical Energy Changes - Prof Klaas Wynne For the following use R= 8.314472 J K mol'. Consider the reaction of carbon dioxide with carbon to form carbon monoxide: CO2(g) + C(s.graphite) = 2 CO(g) The following standard heats of combustion are given: C(s, graphite) +O49) CO (9) AHT=-393.5 kJ mol- CO(g) + %0 (9) - CO2 (g) AH+283.0 kJ mor" X 2 Q42. Using Hess's Law, calculate the standard enthalpy change AH" for the above reaction (in kJ mot'). [1] (A) -959.5 (B) -676.5 (C) -110.5 (D) 1725 + The following standard entropies are given Substance S" (298 K)/(JK mol') C(s, graphite) 5.6 ] 2193 CO2(9) 213.7 CO(g) 197.7 395.4 Q43. Calculate the change in entropy for the reaction above (in JK-mor). [1] (A) -21.6 (B) 176. (C) 1873 (D) 614.7 Q44. Assuming that the standard enthalpy and entropy changes are independent of tem- perature, calculate the reaction Gibbs free energy AG at 1000 °C for the reaction above (in kJ mol-') [1] (A) 224 x 10 (B) -5174 (C) 3.6 (D) 397 Q45. Assuming that the standard enthalpy and entropy changes are independent of tem- perature, calculate the equilibrium constant Key of the reaction above at 1000 °C. [1] (A) 0.0076 (B) 1.005 (C) 1.54 (D) 132 Q46. The equilibrium constant of the above reaction in terms of the activities of the reac- tants and products can be written as: [1] [COM PE (A) (B) K = (C) Pro [co, PC) [CO] Q47. For the above reaction at equilibrium, if the partial pressure of carbon dioxide gas is pcoz = 2 bar, calculate the pressure of carbon monoxide gas at 1000 °C (in bar). [1] (A) 1.41 (B) 8.1 16.2 (D) 4351 (C)