Chem 113 1st Edition Lecture 13Outline of Last Lecture I. Multi-step reactionsII. A reaction mechanismOutline of Current LectureI. The rate-determining step of a reactionII. Pseudo-First-Order ReactionsIII. Reaction energy diagram for two-step reactionCurrent LectureI. The rate-determining step of a reactiona. The slowest step in a reaction is the rate-determining or rate-limiting stepb. The rate law for the rate-determining step becomes the rate law for the overall reactionII. Pseudo-First-Order Reactionsa. For the reaction: 2NO2(g) +F2 (g)2NO2F (g), Rate=k[NO2][F2]i. The integrated rate law for this reaction is complex, but we can modify the expression to make it easier1. Run with large excess of NO2a. As the reaction proceeds, Δ [NO2] ≈0 while we can measureΔ[F2]2. Since Δ [NO2] ≈0, then [NO2] is constant and k[NO2] becomes k13. Rate is now= k1[F2] and we can apply the 1st order integrated law to find k1III. Reaction energy diagram for two-step reactiona. Each step in a multi-step reaction has its own transition state, which occurs at theenergy maximum for that stepThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.b. Diagrams will have two humps indication two activation energies for each of the steps in the overall
View Full Document