IMG_0004_NEW_0033 - Different phase from reactants...

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Reaction Profiles and Transition States Rate of reaction determined by activation energy, Eu (and frequency factor, A) Fgr single step reactions: Exothemic reaction o o o E o o L Provides an alternative reaction mechanism with a lower activation energy Does not affectthe energy difference ( E) between products and reactants Does not affect equilibrium between products and reactants Endothermic reaction s) o c o (B .F c o o (L E"(uncatalysed) Products Reaction coordinate Reditr Fogfess Reaclion Progre$ Example: \2 reaction Reactmts Transition State Products ""\ f"' /""" Ho- + rf$ric-Br --=* "?-:$-{-"' * "*"1,,," * "'- " a "--r,\ H Bond forming Bond breaking Catalysis Catalysfi Substance that speeds up a chemical reaction without being consumed In same phase as reactants: homogeneous
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Unformatted text preview: Different phase from reactants: heterogeneous Multi-Step Reaction Profiles . Rate of reaction determined by activation energy, E o (and frequency factor, A) . For multiple step reaction: t"(Step 1) E"(Step 2) E"(Step 3) p,alwt AE 'i6 c o o (L ffi' Reaction coordinate To increase overall rate =+ Change:- Conditions- OR Mechanism Reaclion progre$ Heterogeneous Gatalys is Hydrogenation of Ethylene O Adsorption of reactants O Migration/diffi.rsion of surface-adsorbed reactants €) Reaction on the surface O Desorption of products Examples: Catalytic converter CO+NO tvletaloxids.Pt.Pd CO, +N, Haber process [email protected] 2NH,...
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This note was uploaded on 12/27/2011 for the course CHEM 122 taught by Professor Williams during the Fall '10 term at Simon Fraser.

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