Elementary Principles 414

# Elementary Principles 414 - 9.51 (cont'd) Reference states:...

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9- 62 c. Reference states: CH g , C H g , N g , O g , H O l , CO (g) at 25 C 42 6222 2 o bg For a constant volume process the heat released or absorbed is determined by the internal energy of reaction. Substance mol kJ mol mol kJ mol CH CH O CO HOv in in out out 4 26 2 2 n U n U U ±± . . .. . . ± 085 0 015 0 2 225 0 0 223 0 115 0 215 2 1 −− ± . . . UU H R T 1 25 25 44 01 8314 1000 4153 ==− = = ΔΔ v o v o CC k J / m o l J 1 kJ 298 K mol K J kJ mol ej Eq. (9.1-5) () UH R T c o c o i gaseous products i gaseous reactants =− νν ⇒= Δ Δ ± . .) . ± . ) . U U c o CH 3 c o 3 4 kJ mol J 298 K (1+ 2 kJ mol K 10 J kJ mol kJ mol J 298 K (3+ 2 kJ mol K kJ mol 89036 8 314 1 2 1 890 36 1559 9 35 1 1 156114 Energy balance : Q U n U n U nU Q ii == + + + += ⇒− = Δ CH c o CH c o out in 6 2 4 4 mol/s kJ mol C H mol / s H O kJ / mol kJ kJ (transferred from reactor) ± ² ± . . b g b g b g 890 36 156114 4153 902 902 Since the O 2 (and N 2 if air were used) are at 25 ° C at both the inlet and outlet of this process, their specific enthalpies or internal energies are zero and their amounts therefore have no effect on the calculated values of Δ Δ ²
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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.

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