Chemistry 132 NTPowerPoint PresentationRates of ReactionReviewChange of Concentration with TimeSlide 6Concentration-Time EquationsSlide 8Slide 9A Problem To ConsiderSlide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Half-lifeSlide 28Figure 13.8Slide 30Slide 31Slide 32Slide 33Graphing Kinetic DataSlide 35Slide 36Slide 37Slide 38Slide 39Plot of log [N2O5] versus time.Figure 13.9Slide 42Slide 43Figure 13.10 Plotting the data for the decomposition of nitrogen dioxide at 330°C.Slide 45Slide 46HomeworkOperational SkillsSlide 49111111Chemistry 132 NTMore can be accomplished with the phrase “I must do something” than with the phrase “something should be done”.Anon222222Rates of ReactionChapter 13Module 2Section 13.4The burning of steel wool444444ReviewThe effect of concentration on reaction rate.Determination of the Rate Law for a given reaction by the method of initial rates.555555Change of Concentration with TimeA rate law simply tells you how the rate of reaction changes as reactant concentrations change.A more useful mathematical relationship would show how a reactant concentration changes over a period of time.666666Change of Concentration with TimeA rate law simply tells you how the rate of reaction changes as reactant concentrations change.Using calculus we can transform a rate law into a mathematical relationship between concentration and time.This provides a graphical method for determining rate laws.777777Concentration-Time EquationsZero-Order Rate LawSuppose we look at a simple generic zero order reaction of the reactant “A” to form products.products A Remember that the rate of this reaction is unaffected by the concentration of “A”.kk[A]RateoIt’s Rate Law would be:888888Concentration-Time EquationsZero-Order Rate LawYou could write the rate law in the form;k]A[k t]A[ RateoUsing calculus, we can derive the following relationship between [A] and time,”t”.ot]A[kt]A[ 999999Concentration-Time EquationsZero-Order Rate LawYou could write the rate law in the form;k]A[k t]A[ RateoHere [A]t is the concentration of reactant A at time t, and [A]o is the initial concentration.ot]A[kt]A[ 101010101010A Problem To ConsiderSuppose that the decomposition of a hypothetical compound “A” is zero order with a rate constant of 1.8 x 10-4 (mol/L.s). If the initial concentration of “A” is 1.00 mol/L, what is the concentration of “A” after 600 seconds?The zero-order concentration-time equation for this reaction would be:ot]A[kt]A[ 111111111111A Problem To ConsiderSuppose that the decomposition of a hypothetical compound “A” is zero order with a rate constant of 1.8 x 10-4 (mol/L.s). If the initial concentration of “A” is 1.00 mol/L, what is the concentration of “A” after 600 seconds?L/mol )]00.1()600)(108.1([]A[4tSubstituting the given information we obtain:L/mol )]00.1()108.0([]A[tL/mol 892.0]A[t121212121212Concentration-Time EquationsFirst-Order Rate LawSuppose we look at a simple generic first order reaction of the reactant “A” to form products.products A In a first-order reaction, the rate is directly proportional to the concentration of “A”.k[A]Rate Its Rate Law would be:131313131313Concentration-Time EquationsFirst-Order Rate LawYou could write the rate law in the form;]A[k t]A[ Rate 141414141414Concentration-Time EquationsFirst-Order Rate LawUsing calculus, you get the following equation.kt- ]A[]A[lnotHere [A]t is the concentration of reactant A at time t, and [A]o is the initial concentration.The ratio [A]t/[A]o is the fraction of A remaining at time t.151515151515A Problem To ConsiderThe decomposition of N2O5 to NO2 and O2 is first order with a rate constant of 4.8 x 10-4 s-1. If the initial concentration of N2O5 is 1.65 x 10-2 mol/L, what is the concentration of N2O5 after 825 seconds?The first-order time-concentration equation for this reaction would be:kt- ]ON[]ON[lno52t52?161616161616A Problem To ConsiderThe decomposition of N2O5 to NO2 and O2 is first order with a rate constant of 4.8 x 10-4 s-1. If the initial concentration of N2O5 is 1.65 x 10-2 mol/L, what is the concentration of N2O5 after 825 seconds?Substituting the given information we obtain:s) 825()s10(4.80- L/mol1065.1]ON[ln1-4-2t52171717171717A Problem To ConsiderThe decomposition of N2O5 to NO2 and O2 is first order with a rate constant of 4.8 x 10-4 s-1. If the initial concentration of N2O5 is 1.65 x 10-2 mol/L, what is the concentration of N2O5 after 825 seconds?Substituting the given information we obtain:0.396- L/mol1065.1]ON[ln2t52181818181818A Problem To ConsiderThe decomposition of N2O5 to NO2 and O2 is first order with a rate constant of 4.8 x 10-4 s-1. If the initial concentration of N2O5 is 1.65 x 10-2 mol/L, what is the concentration of N2O5 after 825 seconds?Taking the inverse natural log of both sides we obtain:673.0 L/mol1065.1]ON[0.396-2t52e191919191919A Problem To ConsiderThe decomposition of N2O5 to NO2 and O2 is first order with a rate constant of 4.8 x 10-4 s-1. If the initial concentration of N2O5 is 1.65 x 10-2 mol/L, what is the concentration of N2O5 after 825 seconds?Solving for [N2O5] at 825 s we obtain:L/mol 0111.0)673.0()L/mol101.65(]O[N2-52(see Exercise 13.5 and Problem 13.49)202020202020A Problem To ConsiderIn the presence of excess thiocyanate ion, SCN-, the following reaction is first order in iron(III) ion, Fe3+; the rate constant, k, is 1.27 h-1.How many hours are required for this reaction to reach 90% completion?(aq)Fe(SCN)(aq)SCN (aq)Fe2-3 First, we must note that a 90% completion implies that only 10% of the reactants are left. This implies10.0][Fe][Feo3t3212121212121A Problem To ConsiderIn the presence of excess thiocyanate ion, SCN-, the following reaction is first order in iron(III) ion, Fe3+; the rate constant, k, is 1.27 h-1.How many hours are required for this reaction to reach 90% completion?(aq)Fe(SCN)(aq)SCN (aq)Fe2-3 Going to our first-order concentration-time equation, we obtain:kt][Fe][Felno3t3222222222222A Problem To ConsiderIn the presence of excess thiocyanate ion, SCN-, the following reaction is first order in iron(III) ion, Fe3+; the rate constant, k, is 1.27 h-1.How many hours are required for this reaction to reach