CHEM 1200 1nd Edition Lecture 5Outline of Last Lecture I. Chapter IntroII. Reaction Ratesa. –1/a(ΔA/Δt) = -1/b (ΔB/Δt) = 1/c (ΔC/Δt) = 1/d (ΔD/Δt)III. Concentration and Ratea. Rate Law: k x [A]^m x [B]^nb. What factors affect speed of reactioni. Reactant physical stateii. Reactant concentrationiii. Temperatureiv. Catalystsc. Average Rate vs Instantaneous Rated. Units of Rate ConstantsOutline of Current Lecture I. Method of initial Ratesa. How to calculate Rate orderi. Rate 2/Rate 1 = [A]^n x [B]^m x [C]^p (for rate 2) / [A]^n x [B]^m x [C]^p (for rate 1)II. Concentration and Timea. Zeroth-Order reactionb. First-Order reactionc. Logarithm ReviewThese 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.d. Confirming First Order Reactionse. Second-Order ReactionsCurrent LectureI. Method of Initial Ratesa. How are rate laws determined? MUST be determined experimentallyb. Method of initial rates: determines reaction orders from the effect of changing a reactant’s concentration on the initial rate of the reactionc. How to calculate rate order (Know how to do this!)i. Rate 2/Rate 1 = [A]^n x [B]^m x [C]^p (for rate 2) / [A]^n x [B]^m x [C]^p (for rate 1)II. Concentration and Timea. Zeroth-order reaction: A + bB productsi. [A] at time t = -kt + [A] initiallyb. First order reactioni. Ln[A] = -kt + ln[A] initiallyii. [A] = [A] initially e^-kt1. No units!c. Logarithm Review (Must know these! Will not be given on exam!)i. Ln A/B = ln A – ln Bii. Ln A^n = n ln Aiii. Ln (A x B) = ln A + ln Biv. Ln e^x = xd. Confirming First-Order Reactions using Concentration vs Time Datai. Graph should exponentially decayii. Graph t and ln [A] linear=first order reactioniii. Slope of line is rate constant, k1. Rate constants are never negativee. Second-Order reactionsi. 1/[A] = kt + 1/[A] initiallyii. Plot t against ln [A] and 1/[A]1. Whichever is linear tells you what order it
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