a catalyst increases the rate of they provide an lowera catalyst increases the rate of a rxn without...
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A catalyst increases the rate of a rxn without being consumed.
They provide an alternate mechanism.
Lower activation energy.
Ex: O3(g) + O(g) 2 O2(g)
Decomposition of O3 catalyzed with Cl from CFCs.
Cl + O3 ClO + O2
ClO + O Cl + O2
Homogeneous catalysts exist in the same phase as reactants.
Heterogeneous catalysts exist in a different phase than reactants.
Gas or liquid reactants adsorb, or stick to a solid surface.
Catalytic converter – pollutants in car exhaust stick to Pt/Pd surface to break down.
Hydrogenation – alkenes (C=C) convert to alkanes (C-C) on Pt surface.
Four Steps: 1. Adsorption of reactants. 2. Diffusion (migration) until
reactants approach each other. 3. Reaction to form products. 4. Desorption of products.
Enzymes – biological protein catalysts.
Both homogeneous and heterogeneous properties.
Reactants called substrates and bond to active site.
Read section 12.8
Ch. 12: #65-70 all
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