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Unformatted text preview: 3 gC 1T2 * R uT ln PC 4 * nD 3 g D 1T 2 nA 3 g A 1T2 * R uT ln PD 4 R uT ln PA 4 nB 3 gB 1T2 * R uT ln PB 4 where gi* (T) represents the Gibbs function of component i at 1 atm pres- | 797 0 For convenience, we define the standard-state Gibbs function change as
G* 1T2 nC gC 1T2 * nD g D 1T2 * nA g A 1T2 *
nB ln P B 2 nB gB 1T2 * (1611) Substituting, we get
G* 1T 2 R uT 1nC ln P C nD ln P D nA ln P A R uT ln P nCP nD C D (1612) P nAP nB A B Now we define the equilibrium constant KP for the chemical equilibrium of ideal-gas mixtures as
KP P nCP nD C D P nAP nB A B
(1613) Substituting into Eq. 1612 and rearranging, we obtain
G*1T2>RuT (1614) Therefore, the equilibrium constant KP of an ideal-gas mixture at a specified temperature can be determined from a knowledge of the standard-state Gibbs function change at the same temperature. The KP values for several reactions are given in Table A28. Once the equilibrium constant is available, it can be used to determine the equilibrium compositio...
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This note was uploaded on 06/15/2009 for the course MAE 3311 taught by Professor Hajisheik during the Summer '08 term at UT Arlington.
- Summer '08