CH E_00001 - CHAPTER NINE 4 NH 3 (g) + 5O 2 (g) 4NO(g) + 6H...

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9- 1 CHAPTER NINE 9.1 9.2 a. b. c. d. e. f. a. b. c. 45 904 7 3 NH g O g) 4NO(g) + 6H O(g) kJ / mol 22 r o () ( ± . +→ =− Δ H When 4 g-moles of NH 3 (g) and 5 g-moles of O 2 (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. 2 5 2 3 NH g O g) 2NO(g) + 3H O(g) ( Reducing the stoichiometric coefficients of a reaction by half reduces the heat of reaction by half. Δ ± . . H r o kJ / mol 904 7 2 452 4 NO(g) + 3 2 HO (g ) NH g O g ) →+ 3 5 4 ( 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 ± (. ) . H r o kJ / mol =+ 904 7 4 226 2 3 3 3 3 NH NH o 3 NH r 3 3 NH m 340 g/s 340 g 1 mol n2 0 . 0 m o l / s s1 7 . 0 3 g ˆ 20.0 mol NH 904.7 kJ nH QH = 4 . 5 2 1 0 k J / s s4 m o l N H ν = == Δ = × ² ² ² ² ² The reactor pressure is low enough to have a negligible effect on enthalpy.
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This note was uploaded on 01/07/2012 for the course CH E 210H at Pennsylvania State University, University Park.

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