Chapter x Kinetics of Complex reactions 8 10. 1 Typical complex reactions Outside classroom reading Levine: p559 17.9
Chapter X Kinetics of Complex Reactions Outside classroom reading: Levine: p.559 17.9 §10.1 Typical complex reactions
8 10.1 Typical complex reactions The kinds of typical complex reactions The most simple complex reaction is composed of two elementary steps aa+bB g+hh 1)Opposing reaction Reversible reaction K1B 2)Parallel reaction ompteting reactio C A-M>B-2>C 3)Consecutive Reaction
The kinds of typical complex reactions 2) Parallel Reaction Compteting reaction A B C 1 2 ⎯⎯→ ⎯⎯→ k k 3) Consecutive Reaction 1) Opposing Reaction Reversible reaction §10.1 Typical complex reactions The most simple complex reaction is composed of two elementary steps
8 10.1 Typical complex reactions 10.1.1 Opposing Reaction/reversible reaction The forward and the backward /reverse reaction take place simultaneously aa tbB hH for opposing reaction consisting of elementary k_AB=kgh reactions n=KAB K [G]HI KK k AlB k r=kgh As reaction proceeds, r, increases while r The connection between the equilibrium constant(K] and the rate coefficients of decreases. When r+ becomes equal to r simple reactions. This relation, named as equilibrium is reached kinetic equilibrium constant Can we extend this discussion to ammonia synthesis?
10.1.1 Opposing Reaction / reversible reaction The forward and the backward / reverse reaction take place simultaneously. for opposing reaction consisting of elementary reactions: [A] [B] a b r k + + = [G] [H] g h r k − − = As reaction proceeds, r+ increases while r− decreases. When r+ becomes equal to r− , equilibrium is reached. [A] [B] [G] [H] a b g h k k + − = [G] [H] [A] [B] g h a b c k K k + − = = − + = k k Kc The connection between the equilibrium constant (Kc ) and the rate coefficients of simple reactions. This relation, named as kinetic equilibrium constant. Can we extend this discussion to ammonia synthesis? §10.1 Typical complex reactions
810 1 Typical complex reactions 10.1.1 Opposing Reaction/reversible reaction (2)rate equation Under equilibrium conditions For first-first order opposing reaction k(a-x)=kx k(a-xe) B x X.-X t=0 k fe k t (x-x The total rate is a-x xe dx k(a-x)-k at
For first-first order opposing reaction: (2) rate equation t = 0 a 0 The total rate is k a x k x dt dx = + − − − ( ) e e k a x k x ( ) + − − = e e k a x ( ) k x + − − = Under equilibrium conditions e e dx ( ) x x k a dt x + − = t = t e a-xe xe t = t a-x x 10.1.1 Opposing Reaction / reversible reaction e e e ln ( ) x x k at x x + = − e e e ln ( ) a x x k at x x − − = − §10.1 Typical complex reactions
8 10.1 Typical complex reactions 10.1.1 Opposing reaction /reversible reaction a-x k Principle of relaxation method for n k In at (x-x) at x。-x studying fast reaction k+ and k can be determined by measuring The time required for the equilibrium to resume after disturbance x at t and at equilibrium concentration k tk==In er opposing reactions t (x-x 1-2 opposing reaction A kB+C =(k++k)=kt (x。-x) Why opposing reaction a+B C+D
k+ and k− can be determined by measuring x at t and at equilibrium concentration. Principle of relaxation method for studying fast reaction 10.1.1 Opposing Reaction / reversible reaction e e e ln ( ) x x k at x x + = − e e e ln ( ) a x x k at x x − − = − e e 1 ln ( ) x k k t x x + − + = − e e ln ( ) ( ) x k k t kt x x = + = + − − Why? §10.1 Typical complex reactions 1-2 opposing reaction 2-2 opposing reaction Other opposing reactions The time required for the equilibrium to resume after disturbance