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Unformatted text preview: elementary reactions. At Equilibrium: Rate (forward reaction) = Rate(reverse reaction) 2
kf [N2O4] = kr [NO2] k f [NO 2 ]2 = = constant k r [N 2O 4 ] k f = K c = equilib rium con stant k r implies mo lar concentration In General: aA + bB K c = ¾¾
¬¾ ¾ cC + dD d [C]c [D] [A]a [B]b [C], [D] = mo lar concentrations (mo larit ies) of the products at equilibrium [A], [B] = mo lar concentrations (mo larit ies) of the reactants at equilibrium
· This relat ionship was postulated by two chemists in 1864 and called the law of mass action. 5 Chemistry 102 Chapter 14 EQUILIBRIUM CONSTANT
· The Equilibrium Constant, Kc, is a constant for a particular reaction at a given temperature. NOTE: 1. If the overall react ion occurs by a mult istep mechanism, one can show that Kc for the overall reaction equals a product of ratios of the individual rate constants. 2. It is co mmo n practice to write Kc wit hout units Example 1: Write the equilibrium constant expressio n for the equation shown below: ¾¾
2 NO2 (g) + 7 H2 (g) ¬¾ 2 NH3 (g) + 4 H2O(...
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