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Unformatted text preview: must be exactly the same ones appearing in the table from which the KP values are selected. Multiplying all the coefficients of a stoichiometric equation does not affect the mass balance, but it does affect the equilibrium constant calculations since the stoichiometric coefficients appear as exponents of partial pressures in Eq. 1613. For example,
1 2 O2 | 801 H 2O K P1 PH2O
1>2 PH2P O2 H H+ + e NH+ Ne NH
nH n + H n e KP = But for 2H 2 O2 2H 2O K P2 P 2 2O H P 2 2PO2 H 1K P1 2 2 ( ( n P Ntotal where Ntotal = NH + NH+ + Ne n = nH+ + ne n H =1+11 =1 7. Free electrons in the equilibrium composition can be treated as an ideal gas. At high temperatures (usually above 2500 K), gas molecules start to dissociate into unattached atoms (such as H2 2H), and at even higher temperatures atoms start to lose electrons and ionize, for example,
H H e (1616) The dissociation and ionization effects are more pronounced at low pressures. Ionization occurs to an appreciable extent only at very high temperatures, and the mixture of electrons, ions, and neutral atoms can be treated as an ideal gas. Therefore, the equilibrium composition of ionized gas mixtures...
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- Summer '08