Question

8. From standard enthalpies of formation, standard entropies, and standard heat capacities available from tables in the Data section (pp 572-579), calculate the standard enthalpies and entropies at 298 K and 398 K for the reaction CO2(g)+ H2(g) -> CO(g) + H20(g). Assume that the heat capacities are constant over the temperature range involved. Recall that the standard reaction enthalpy and entropy are given by Products Reactants 0 7n 0 Products Reactants List the fundamental concepts involved in this problem.]

Answer 1

Delta_r H^0 = summation_products v Delta_f H^0 - summation_reactants v Delta_f H^0 [2.34 a] Delta_r H^0 (298 k) = 1 times Delta_f H^0 (CO, g) + 1 times Delta_f H^0 (H_2 O, g) - 1 times Delta_f H^0 (CO_2 g) = {- 110.53 - 241.82 -(-393.51)} kJ mol^-1 = + 41.16 kJ mol^-1 Delta_r S^0 (298 k) = 1 times S^0_m (CO, g) + 1 times S^0_m (K_2 O, g) - 1 times S^0_m (H_2, g) = (197.67 + 188.83 - 213.74 - 130.684)kJ mol^-1 = + 42.08 J K^-1 mol^-1 Delta_r H^0 (398 k) = Delta_r H^0 (298 k) + integral^198k_298k Delta_r C^0_p dT [2.36 a] = Delta_r H^0 (298 k) + Delta_r C^0_p Delta T [heat capacities constant] Delta_r C^0_P = 1 times C^0_p.m (CO, g) + 1 times C^0_p.m (H_2 O, g) - 1 times C^0_pm (CO_2, g) - 1 times C^0_p, m (H_2 g) = (29.14 + 33.58 - 37.11 - 28.824) J K^-1 mol^-1 = -3.21 K K^-1 mol^-1 Delta_t H^0 (398 k) = (41.16 kJ mol^-1) + (-3.21 JK^-1 mol^-1)..