Thermodynamics filled in class notes_Part_78

Thermodynamics filled in class notes_Part_78 - 5.3. FIRST...

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Unformatted text preview: 5.3. FIRST LAW ANALYSIS OF REACTING SYSTEMS 163 5.3 First law analysis of reacting systems One can easily use the first law to learn much about chemically reacting systems. 5.3.1 Enthalpy of formation The enthalpy of formation is the enthalpy that is required to form a molecule from combining its constituents at P = 0 . 1 MPa and T = 298 K . Consider the reaction (taken here to be irreversible) C + O 2 → CO 2 . (5.123) In order to maintain the process at constant temperature, it is found that heat transfer to the volume is necessary. For the steady constant pressure process, one has U 2 − U 1 = 1 Q 2 − 1 W 2 , (5.124) = 1 Q 2 − integraldisplay 2 1 PdV, (5.125) = 1 Q 2 − P ( V 2 − V 1 ) , (5.126) 1 Q 2 = U 2 − U 1 + P ( V 2 − V 1 ) , (5.127) = H 2 − H 1 , (5.128) 1 Q 2 = H products − H reactants . (5.129) So 1 Q 2 = summationdisplay products n i h i − summationdisplay reactants n i h i . (5.130) In this reaction, one measures that 1 Q 2 = − 393522 kJ for the reaction of 1...
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This note was uploaded on 11/26/2011 for the course EGN 3381 taught by Professor Park-sou during the Fall '11 term at FSU.

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Thermodynamics filled in class notes_Part_78 - 5.3. FIRST...

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