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Unformatted text preview: reverse reaction be favored? (would reactants be favored?)
· To answer this, a new quant it y is introduced: Qc = the Reaction Quotient = has the same form as Kc but the concentrations used to calculate its value are not equilibrium concentrations. Qc = [CH 4 ][H 2 O] (1.00x103 M)(1.00x103 M) = = 6.25 3 [CO][H 2 ]
(2.00x102 M)(2.00x102 M) Kc = 3.92 Qc = 6.25 should decrease to
· For the reaction mixture to reach equilibrium: Qc Qc decreases if: Ø Ø 3.92 [CH4], [H2O] decreases [CO], [H2] increases CO (g) + 3H2 (g) CH4 (g) + H2O(g) Ø The reaction goes to the left Ø Reverse react ion is favored Ø Formation of reactants is favored Qc = 0 Qc = ¥ K c Forward Rxn Reactants Reverse Rxn Equilibrium Increasing Qc 15 Products Chemistry 102 Chapter 14 PREDICTING THE DIRECTION OF REACTION
· In General: For a reaction mixture that is NOT AT EQUILIBRIUM : aA + bB ¾¾
¬¾ ¾ d [C]c [D] Qc = a b [A] [B] cC + dD Compare: Qc to Kc · If: Qc > K c Reaction will go the left ( )...
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