9- 1CHAPTER NINE 9.1 9.2 a. b. c. d. e. f. a. b. c. 45904 73NH gO g)4NO(g) + 6H O(g)kJ / mol22ro()(±.+→=−ΔHWhen 4 g-moles of NH3(g) and 5 g-moles of O2(g) at 25°C and 1 atm react to form 4 g-moles of NO(g) and 6 g-moles of water vapor at 25°C and 1 atm, the change in enthalpy is -904.7 kJ. Exothermic at 25°C. The reactor must be cooled to keep the temperature constant. The temperature would increase under adiabatic conditions. The energy required to break the molecular bonds of the reactants is less than the energy released when the product bonds are formed. 2523NH gO g)2NO(g) + 3H O(g)(Reducing the stoichiometric coefficients of a reaction by half reduces the heat of reaction by half. Δ±..HrokJ / mol904 72452 4NO(g) +32HO(g)NH gO g)→+354(Reversing the reaction reverses the sign of the heat of reaction. Also reducing the stoichiometric coefficients to one-fourth reduces the heat of reaction to one-fourth. Δ±(.).HrokJ / mol−=+904 74226 23333NHNHo3NHr33NHm340 g/s340 g1 moln20.0mol/ss17.03gˆ20.0 mol NH904.7 kJnHQH=4.5210kJ/ss4molNHν===−Δ=Δ=×²²²²²The reactor pressure is low enough to have a negligible effect on enthalpy.
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This note was uploaded on 02/27/2012 for the course CHEMICAL E 312 taught by Professor Cheung during the Fall '11 term at The University of Akron.