IMG_0004_NEW_0030 - intermediates O Write reaction...

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Testing the Rate Law Experimentally Vary reactant concentrations -+ Does rate law predict experiment result? O High tHzl = k2lH2l >> k-l -ry=/qlNol'z Predict: reaction rate will show 2od-order dependence on [NO] only O Low [Hz] + kzltlzl << k-l Rate : -qEl,l- Predict: reaction rate will show 2d-order dependence on [NO] and lr order dependence on [Hr] Reaction Rate versus Temperature Rate constents (t) increase with temperature (in general) Svante August Arrhenius ( I 859 - 1927): plot of ln(f) versus l/T (in Kelvin) gives a straight line 1889, Arrhenius: Activation Enerry : critical energy that chemicals need to react 7 k, -l dt Steady-State Approxi mation Step-by-Step GOAL: To write the rate law without including any
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Unformatted text preview: intermediates O Write reaction mechanism in terms of elementary reaction steps O Write the rate law for intermediates dilrternedia tel _ dt Apply stead-state approximation d[Internredia te] _ O dt Use O and I to solve for [Intermediate]: [Intermediate] : ... Write rate law for reactant, including dependence on [Intermediate] dfReactart] dt Substitute expression for [Intermediate] into rate law for reactant Arrhenius Equation Plot of ln(fr) versus l/T gives a straight line. Equation for this relationship: frequency factor ,-- Activation Energ;r t_L A E&quot;,r1) ktk:WA)-,n,[rJ 'r Universal Gas Constant (8.3145 JKimolr) k = 4s-E&quot;lnr Alternatively we can write this as:...
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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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