Presentation is loading. Please wait.

Presentation is loading. Please wait.

Reaction Rates I. Expressing Reaction Rates-________ ____, or the ____ at which a _________ ________ occurs, is expressed in terms of ______ in ____________.

Similar presentations


Presentation on theme: "Reaction Rates I. Expressing Reaction Rates-________ ____, or the ____ at which a _________ ________ occurs, is expressed in terms of ______ in ____________."— Presentation transcript:

1 Reaction Rates I. Expressing Reaction Rates-________ ____, or the ____ at which a _________ ________ occurs, is expressed in terms of ______ in ____________ of a ________ or _______ per unit ____ reactionrate chemicalreaction change concentrationreactant producttime 1CO (g) 1NO 2(g) +1CO 2(g) 1NO (g) + What is the reaction rate of the following reaction, in moles/liter·second, if the concentration of NO is 0.000 moles/liter at t 1 = 0.00 seconds and 0.010 moles/liter 2 seconds after the reaction begins? =Average reaction rate Δt (t 2 – t 1 ) Δquantity Average reaction rate= 0.010 M – 0.000 M 2.00 s – 0.00 s Average reaction rate=0.0050 mol/L·s

2 Reaction Rates I. Expressing Reaction Rates 1C 4 H 9 Cl1H 2 O+1C 4 H 9 OH1HCl+ What is the reaction rate of the following reaction, in moles/liter·second, if the concentration of C 4 H 9 Cl is 0.220M at t 1 = 0.00 seconds and 0.100 M 4.00 seconds after the reaction begins? =Average reaction rate ΔtΔt Δquantity Average reaction rate= 0.100 M – 0.220 M 4.00 s – 0.00 s Average reaction rate=0.0300 mol/L·s -________ ____ can be expressed as the ____ at which a ________ is produced or the ____ at which a ________ is consumed reactionrate product rate reactant brackets indicate the concentration of butyl chloride

3 Reaction Rates I. Expressing Reaction Rates 1H 2 1Cl 2 +2HCl What is the reaction rate of the following reaction, in moles/liter·second, expressed in moles of H 2 consumed, if the concentration of H 2 is 0.030M at t 1 = 0.00 seconds and 0.020M 4.00 seconds after the reaction begins? =Average reaction rate ΔtΔt Δquantity Average reaction rate= 0.020 M – 0.030 M 4.00 s – 0.00 s Average reaction rate=0.0025 mol/L·s 0.010 moles H 2 x 2 moles HCl ______________ 1 mole H 2 =0.020 moles HCl

4 Reaction Rates I. Expressing Reaction Rates 1H 2 1Cl 2 +2HCl What is the reaction rate of the following reaction, in moles/liter·second, expressed in moles of HCl produced, if the concentration of HCl is 0.000M at t 1 = 0.00 seconds and 0.020M 4.00 seconds after the reaction begins? =Average reaction rate ΔtΔt Δquantity Average reaction rate= 0.020M – 0.000M 4.00 s – 0.00 s Average reaction rate=0.0050 mol/L·s

5 Reaction Rates I. Expressing Reaction Rates 2H 2 O 2 1O 2 + 2H 2 O What is the reaction rate of the following reaction, in moles/liter·minute, expressed in moles of H 2 O 2 consumed, if the concentration of H 2 O 2 is 2.50M at t 1 = 0.00 minutes and 2.12M 2.00 minutes after the reaction begins? =Average reaction rate ΔtΔt Δquantity Average reaction rate= 2.12M – 2.50M 2.00 min – 0.00 min Average reaction rate=0.19 mol/L·min

6 Reaction Rates I. Expressing Reaction Rates 2H 2 O 2 1O 2 + 2H 2 O What is the reaction rate of the following reaction, in moles/liter·minute, expressed in moles of O 2 produced, if the concentration of H 2 O 2 is 1.82M at t 1 = 0.00 minutes and 1.48M 5.00 minutes after the reaction begins? =Average reaction rate ΔtΔt Δquantity Average reaction rate= 0.17M – 0.00M 5.00 min – 0.00 min Average reaction rate=0.034 mol/L·min 0.34 moles H 2 O 2 x 1 mole O 2 ______________ 2 mole H 2 O 2 =0.17 mole O 2

7 Reaction Rates II. The Collision Theory Look at the picture of the cars to the right. Observe their position and orientation. What do you predict happened to the cars? Why do some of the cars appear to be more damaged than others? -the _________ ______ states that, in order for a ________ ________ to take place, the ______, ____, or _________ must _______ in order to _____ CollisionTheory chemicalreaction atomsionsmolecules collidereact

8 Reaction Rates II. The Collision Theory-according to the _________ ______, ___ and ___ molecules must _______ in order to _____, but in the reaction of ______ ________ and ________ ______, only a _____ _______ of the _________ produce ________. ____ Collision 1Cl 2 1H 2 +2HCl Theory Cl 2 H2H2 collide react 1CO (g) 1NO 2(g) +1CO 2(g) 1NO (g) + CarbonmonoxideNitrogendioxide smallfractioncollisions reactionsWhy?

9 Reaction Rates II. The Collision Theory CONO 2 Collision CONO 2 Rebound Incorrect orientation CONO 2 Collision CO NO 2 Rebound Incorrect orientation

10 Reaction Rates II. The Collision Theory CONO 2 Collision Correct orientation Activated complex CO 2 NO Cl 2 H2H2 Collision Orientation Always Correct

11 Reaction Rates II. The Collision Theory-according to the _________ ______, the _________ of ________ _________ must __ _______, __ _______ with the correct ___________, and __ _______ with sufficient ______ to form the _________ _______ CollisionTheory particlesreactingsubstances 1.collide2.collide orientation3.collide energy activationcomplex CONO 2 Collision CONO 2 Rebound Insufficient energy

12 Reaction Rates II. The Collision Theory-the minimum amount of ______ that reacting particles must have to form the ________ _______ is called the ________ ______, or ___ energy activationcomplex activationenergyEaEa -a ____ _________ ______ means that relatively ___ __________ will have sufficient ______ to produce the _________ _______, while a ___ _________ ______ means that _____ __________ will have the required _____ to form the __________ _______, and the _______ ____ will be ______ highactivationenergy fewcollisions energy activationcomplexlow activationenergymany collisionsenergy activationcomplex reactionratehigher If you wanted to travel from Kalispell, Montana, to Browning, you could take the scenic Going-to-the-Sun Highway through Glacier National Park. First, you would have to climb 1100 m to cross the continental divide at Logan Pass, but after that, it would be downhill all the way reactants products activation energy activation complex On the other hand, if you wanted to turn around and go back to Kalispell from Browning, you would only have to climb 700 m to Logan Pass, after which it would be downhill all the way, and you would end up at a lower elevation that when you started

13 Reaction Rates II. The Collision Theory-once ________ ______ has been supplied to the ________, if the ________ end up lying at a _____ ______ _____ than the _________, then ______ is ________ by the _______, and the ______ is __________ -if the ________ end up lying at a _______ ______ _____ than the _________, then ______ is ________ by the _______, and the ________ is __________ activationenergy reactantsproducts lowerenergystate reactantsenergy releasedreaction exothermic productshigher energystatereactants energyabsorbedreaction endothermic

14 Reaction Rates III. Factors Affecting Reaction Rates A. The Nature of the Reactants-one factor that affects the ____ of chemical _________ is the ________ _______ of the ________ rate reactions reactivenature reactants 1Ca (s) 2H 2 O (l) +1Ca(OH) 2(aq) 1H 2(g) + Calcium reacts with cold water to produce Calcium hydroxide and Hydrogen gas 2Na (s) 2H 2 O (l) +2NaOH (aq) 1H 2(g) + Sodium reacts with cold water to produce Sodium hydroxide and Hydrogen gas

15 Reaction Rates III. Factors Affecting Reaction Rates B. Concentration-when the _____________ of the _________ is _________, reactions ______ ___ concentrationreactants increasedspeedup -since _________ is necessary for _________ _________ to take place, __________ the ____________ of the ________ _________ increases the likelihood that the _________ of one ________ will _______ with the _________ of the other _________ collisionchemical reactionsincreasing concentrationreactingparticles reactantcollide particlesreactant 4Fe3O 2 +2Fe 2 O 3 +

16 Reaction Rates III. Factors Affecting Reaction Rates B. Concentration 4Fe3O 2 +2Fe 2 O 3 + The concentration of oxygen in the air is about 21%, so the concentration of pure oxygen is about 5 times higher than that of air

17 Reaction Rates III. Factors Affecting Reaction Rates C. Surface Area-if the _______ _____ of the _____ _____ of reactant is _________ by _________ particle _____, the _______ ____ will ________, since the greater ________ _____ allows the _________ of one ________ to _______ with _____ particles of the other ________ per unit time surfaceareasamemass increasedreducing sizereactionrateincrease surfacearea particlesreactantcollide morereactant 4Fe3O 2 +2Fe 2 O 3 +

18 Reaction Rates III. Factors Affecting Reaction Rates D. Temperature -__________ the ___________ at which a _______ occurs _________ the _______ ____ increasingtemperature reactionincreasesreactionrate -__________ the ___________ _________ the average _______ _____ of the _________ that make up a substance, causing the ________ to _______ more ___________ increasingtemperatureincreases kineticenergyparticles collidefrequently Temperature (in K)Relative Reaction Rate 290 310 320 330 2 8 16 32 Temperature (in K) 0 5 10 15 20 25 30 35 40 280290300310320330 Relative Reaction Rate According to the curve of the graph, what temperature increase, in Kelvin, doubles the rate of reaction? _______K At what Kelvin temperature is the relative reaction rate 25? _______K

19 Reaction Rates III. Factors Affecting Reaction Rates D. Temperature -__________ the ___________ also ________ the ____ of _______ by _________ the _______ of _________ with _________ ________ ______ to cause a _______ increasingtemperatureincreases ratereactionincreasing numberparticlessufficient collisionenergyreaction -__________ the ___________, then, _______ the _______ ____ by _________ the _________ _________ and the _________ ______ increasingtemperatureincreases reactionrateincreasing collisionfrequencycollision energy

20 Reaction Rates III. Factors Affecting Reaction Rates E. Catalysts-_________ are __________ that _______ the _____ of ________ without being _________ by the ________ catalystssubstancesincrease ratereactionconsumed reaction -________ are _________ ________ which cause _________ to happen or happen ______ without _______ the __________, which could ________ living things by __________ their ________ enzymesbiologicalcatalysts reactionsfaster raisingtemperaturedamage denaturingproteins -________ increase ________ ____ by ________ the _________ ______ for a _________, so that ________ that had ____________ energy before now have _________ energy to ______ -_________ make reactions _____ likely to _______ by ________ the __________ ______ catalystsreactionratelowering activationenergyreaction particlesinsufficient sufficientreact inhibitorsless proceedraisingactivationenergy Enzyme Substrate (Reactant)

21 Reaction Rates A. Safety: 1. Hypothesis:What is the effect of temperature on the rate of reaction? 2. Prediction: 3. Gather Data: The surfaces of the hot plates and the water will be hot enough to cause burns. Use caution. B. Procedure: 1. Obtain an effervescent tablet and break it into 4 pieces of roughly equal size. III. Factors Affecting Reaction Rates 2. Measure and record the mass of 1 piece of effervescent tablet.

22 3. Gather Data: B. Procedure: 4. Using a stopwatch to record the elapsed time between the time the reaction begins and the time the reaction ends, drop the tablet into the cup to begin the reaction. Record the time in seconds. 3. Using a 100-mL graduated cylinder, measure 50 mL of room temperature water (about 20°C) into a plastic cup. Measure and record the temperature to the nearest Celsius degree. Reaction Rates III. Factors Affecting Reaction Rates 1C 4 H 8 O 4 4NaHCO 3 + 1NaC 4 H 7 O 4 4H 2 O+ 1H 3 C 6 H 5 O 7 + Citric acidAcetylsalicylic acidSodium bicarbonate Sodium acetyl salicylate 1Na 3 C 6 H 5 O 7 +4CO 2 + Sodium citrateWaterCarbon dioxide

23 3. Gather Data: B. Procedure: Reaction Rates III. Factors Affecting Reaction Rates Temperature (in °C)Mass of Tablet (in g)Reaction Time (in s)Reaction Rate (in g/s) 4. Analyze Data: 5. Repeat steps 2, 3, and 4 twice, except with 50 mL of water at about 50°C, and 65°C. A. Calculate the reaction rate (in g/s) for each of the three trials

24 4. Analyze Data: Reaction Rates III. Factors Affecting Reaction Rates Temperature (in °C) 0.00 01020304050607080 Relative Reaction Rate (in g/s) 90100 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 B. Graph the temperature versus the reaction rate on the following graph, and draw a best-fit curve for the data

25 4. Analyze Data: Reaction Rates III. Factors Affecting Reaction Rates C. Using the data from the graph, predict the reaction rate, in g/s, of the reaction at a temperature of 40°C. _________________ D. Measure and record the mass of the last piece of effervescent tablet. E. Using a 100-mL graduated cylinder, measure 50 mL of water at about 40°C into a plastic cup. Measure and record the temperature to the nearest Celsius degree. F. Using a stopwatch to record the elapsed time between the time the reaction begins and the time the reaction ends, drop the tablet into the cup to begin the reaction. Record the time in seconds, and calculate and record the reaction rate. How does your calculation compare to your prediction?

26 5. Draw Conclusions: using the analysis of the data, answer the question of the hypothesis ________________________________________ ________________________________________ Reaction Rates III. Factors Affecting Reaction Rates

27 Reaction Rates IV. Reaction Rate Laws-when we divide the ________ in _______ ____________, __________ by the _______ in _____, ____, we get an ________ ________ _____ changemolar concentration(Δquantity) changetime(Δt)(Δt) averagereactionrate -chemical reactions tend to _____ _____ as ________ are _________, because in order for a reaction to proceed, _________ must _______, and as _________ are _________ there are ______ ________ left to _______ Hitting the cue ball gives the cue ball kinetic energy, and as it collides with the other balls, they, in turn, receive kinetic energy and collide with other balls Decreasing the number of balls on the table reduces the number of collisions ultimately caused by the initial collision of the cue ball slowdown reactantsconsumed particles collidereactantsconsumed fewerparticlescollide

28 Reaction Rates IV. Reaction Rate Laws-_____ ______ ________ the results of the _________ _______ in terms of a ____________ ___________ between the _____ of a _________ ________ and the ________ _____________ ratelawsquantify collisiontheory mathematicalrelationship ratechemicalreaction reactantconcentration -in the reaction __ ___ __, there is only ___ _________ _______ between the ________ and ________, so the _____ ____ for the reaction is _____ = __ ____, where ____ is the _____________ of the _________ __ and __ is the _____________ __________ _________ ____ ________, which depends on _________ _________, especially the ___________ A→Bone activatedcomplexreactants productsratelaw Ratek[A] concentrationreactantA kexperimentallydetermined specificrateconstant reactionconditions temperature -the ________ _____, then, is _________ _____________ to the _____________ reactionratedirectly proportionalconcentration

29 Reaction Rates V. Reaction Orders-in the reaction __ ___ __, the _____ = __ ___, and it is understood that ____ means the same as ____, and the _________ __ is the ________ ______ A→BRatek[A] [A] 1 2H 2 O 2 2H 2 O1O 2 + exponent1reaction order -the _____ ____ for the _____________ of _____ is _____ = __ ______, and the ________ is said to be _____ _____ in _____ ratelawdecomposition H2O2H2O2 Ratek[H 2 O 2 ] 1 reactionfirstorderH2O2H2O2 ABproducts+ -for _________ with _____ than _____ _______, the _____ ____ is _____ = __ ____ ____ where __ is the _______ _____ for __ and __ is the _______ _____ for __ reactionsmoreone reactantratelaw Ratek[A] m [B] n mreactionorderAn reactionorderB

30 Reaction Rates V. Reaction Orders -an ___________ _______ of evaluating ________ ______is the _______ of _______ ______, in which the ______________ of the _________ are _______ and the effect on the ________ _____ is observed ABproducts+ Trial experimentalmethod reactionordermethodinitial rates -for the ________ that has the _____ ____ _________________, the reaction is described as _______ _____ in ___, _____ _____ in ___, and _____ _____ overall Ratek[NO] 2 [H 2 ] 1 = reactionratelaw secondorderNOfirstorderH2H2 thirdorder 1 Initial [A] (in M) 0.100 Initial [B] (in M) 0.100 Initial Rate (in mol/L·s) 2.00 x 10 -3 2 0.200 0.1004.00 x 10 -3 3 0.200 16.00 x 10 -3 concentrations reactantsvaried reactionrate

31 Reaction Rates V. Reaction Orders-the _____ ____ for this type of reaction is _________________. From the data, you can see that, while ____ was held constant, the ________ _____ has ________ in Trial 2 compared to Trial 1, at the same time ____ has ________, so the ________ ______ __ must equal __, or because ___ = __, __ = __ ratelaw reactionratedoubled [A] doubledreactionorderm 1 Ratek[A] m [B] n = -in Trial 3 compared to Trial 2, ____ is _______, and the _______ ____ ___________, so the ________ ______ __ must equal __, or ___ = __, and the _______ _____ ____ is _________________ and the _______ ________ ______ is ______ _____ _______ [B] doubledreactionratequadruples reactionordern2 overallratelaw Ratek[A] 1 [B] 2 = overallreactionorderthird order(2 + 1) [B] 2m2m 2m1 2n2n 4

32 Given the following experimental data, use the method of initial rates to determine the rate law for the reaction and the overall reaction order. Reaction Rates V. Reaction Orders ABproducts+ Trial 1 Initial [A] (in M) 0.100 Initial [B] (in M) 0.100 Initial Rate (in mol/L·s) 2.00 x 10 -3 2 0.200 0.1002.00 x 10 -3 3 0.200 4.00 x 10 -3 Ratek[A] m [B] n = [A] = 2 m rate = 1 Ratek[A] 0 [B] n = [B] = 2 n rate = 2 Ratek[A] 0 [B] 1 = Ratek[B],=overall reaction order=first order

33 Given the following experimental data, use the method of initial rates to determine the rate law for the reaction and the overall reaction order. Reaction Rates V. Reaction Orders CH 3 CHOCOCH 4 + Trial 1 Initial [CH 3 CHO] (in M) 2.00 x 10 -3 Initial Rate (in mol/L·s) 2.70 x 10 -11 2 4.00 x 10 -3 10.8 x 10 -11 3 8.00 x 10 -3 43.2 x 10 -11 Ratek[CH 3 CHO] m = [CH 3 CHO] = 2 m rate = 4 [CH 3 CHO] = 2 m rate = 4 Ratek[CH 3 CHO] 2,=overall reaction order=second order

34 Given the following experimental data, use the method of initial rates to determine the rate law for the reaction, the overall reaction order, and the value of the specific rate constant. Reaction Rates V. Reaction Orders 2NOCl 2 2NOCl+ Trial 1 Initial [NO] (in M) 0.50 Initial [Cl 2 ] (in M) 0.50 Initial Rate (in mol/L·min) 1.90 x 10 -2 2 1.00 0.507.60 x 10 -2 3 1.00 15.20 x 10 -2 Ratek[NO] m [Cl 2 ] n = [NO] = 2 m rate = 4 Ratek[NO] 2 [Cl 2 ] n = [Cl 2 ] = 2 n rate = 2 Ratek[NO] 2 [Cl 2 ] 1 = overall reaction order=third order,k=0.16 L 2 /mol 2 ·min (or 0.15 L 2 /mol 2 ·min) (or 0.152 L 2 /mol 2 ·min)

35 Given the following experimental data, use the method of initial rates to determine the rate law for the reaction, the overall reaction order, and the value of the specific rate constant. Reaction Rates V. Reaction Orders 2OH - (aq) 2ClO 2(aq) 1ClO 3 - + Trial 1 Initial [ClO 2 ] (in M) 0.0500 Initial [OH - ] (in M) 0.200 Initial Rate (in mol/L·min) 6.90 2 0.100 0.20027.6 3 0.100 13.8 Ratek[ClO 2 ] m [OH - ] n = [ClO 2 ] = 2 m rate = 4 Rate= [OH - ] = ½ n rate = ½ Rate= overall reaction order=third order,k=1.38 x 10 4 L 2 /mol 2 ·min 1ClO 2 - ++1H 2 O (1) k[ClO 2 ] 2 [OH - ] n k[ClO 2 ] 2 [OH - ] 1

36 Given the following experimental data, use the method of initial rates to determine the rate law for the reaction, the overall reaction order, and the value of the specific rate constant. Reaction Rates V. Reaction Orders AB2C+ Trial 1 Initial [A] (in M) 0.010 Initial [B] (in M) 0.010 Initial Rate (in mol/L·s) 0.0060 2 0.020 0.0100.0240 3 0.020 0.0960 Ratek[A] m [B] n = [A] = 2 m rate = 4 Ratek[A] 2 [B] n = [B] = 2 n rate = 4 Ratek[A] 2 [B] 2 = overall reaction order=fourth order,k=6.0 x 10 5 L 3 /mol 3 ·s

37 Given the following experimental data, use the method of initial rates to determine the rate law for the reaction, the overall reaction order, and the value of the specific rate constant. Reaction Rates V. Reaction Orders ABproducts+ Trial 1 Initial [A] (in M) 0.010 Initial [B] (in M) 0.020 Initial Rate (in mol/L·hr) 0.020 2 0.015 0.0200.030 3 0.015 0.040 0.240 Ratek[A] m [B] n = [A] = 1½ m rate = 1½ Ratek[A] 1 [B] n = [B] = 2 n rate = 8 Ratek[A] 1 [B] 3 = overall reaction order=fourth order,k=2.5 x 10 5 L 3 /mol 3 ·hr

38 A chemical reaction involving compound A and compound B as reactants is found to be first order in A and second order in B. What will the reaction rate be for Trial 2? Reaction Rates V. Reaction Orders Trial 1 Initial [A] (in M) 1.0 Initial [B] (in M) 0.20 Initial Rate (in mol/L·s) 0.10 2 2.0 0.60? Ratek[A] m [B] n = Ratek[A] 1 [B] 2 = k=2.5 L 2 /mol 2 ·s 0.10 mol/L·sk(1.0 mol/L) 1 (0.20 mol/L) 2 = Ratek[A] 1 [B] 2 = Rate(2.0 mol/L) 1 (0.60 mol/L) 2 =(2.5 L 2 /mol 2 ·s)=1.8 mol/L·s

39 Reaction Rates V. Reaction Orders-most _________ _________ obey ____ of ______ _____ ______: _____ _____, _____ _____, or _______ _____, and the ______ of the _________ _____ ________, __, vary with the ______ of the ________ chemicalreactionsone threeratelawszeroorderfirst ordersecondorderunits specificrateconstantk orderreaction -if a ________ with ____ or _____ _________ was ______________ __________ to be _____ ______ _______, the _____ _____ would be _____________ or ________________ reactiononemorereactants experimentallydeterminedzero orderoverallratelaw Ratek[A] 0 =Ratek[A] 0 [B] 0 = -in ______ ______ reactions, the _____ _____ is _________, and the ______ of __ are ________ zeroorderratelaw Ratek=unitsk mol/L·s

40 Reaction Rates V. Reaction Orders AB Trial 1 Initial [A] (in M) 2.00 x 10 -3 Initial Rate (in mol/L·s) 1.75 x 10 -11 2 4.00 x 10 -3 1.75 x 10 -11 3 8.00 x 10 -3 1.75 x 10 -11 Ratek[A]m[A]m = [A] = 2 m rate = 1 [A] = 2 m rate = 1 Ratek[A]0,[A]0,=overall reaction order=zero order Ratek=

41 Concentration [A] x 10 -3 (in mol/L) 0.00 1.002.003.004.005.006.007.008.00 Reaction Rate x 10 -11 (in mol/L·s) 9.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 Reaction Rates V. Reaction Orders 10.00 -plot the data from the table on the graph below:

42 Reaction Rates V. Reaction Orders -if a ________ with ____ or _____ _________ was ______________ __________ to be _____ ______ _______, the _____ _____ would be _____________ or ________________ reactiononemorereactants experimentallydeterminedfirst orderoverallratelaw Ratek[A] 1 =Ratek[A] 1 [B] 0 = -in ______ ______ reactions, the _____ _____ is _____________, and the ______ of __ are ____ firstorderratelaw Ratek=unitsk 1/s [A] ABproducts+ Trial 1 Initial [B] (in M) 1.00 x 10 -3 Initial [A] (in M) 1.00 x 10 -3 Initial Rate (in mol/L·s) 2.00 x 10 -11 2 2.00 x 10 -3 1.00 x 10 -3 2.00 x 10 -11 3 2.00 x 10 -3 4.00 x 10 -11 Ratek[A] m [B] n = [B] = 2 n rate = 1 Ratek[A] m [B] 0 = [A] = 2 m rate = 2 Ratek[A] 1 [B] 0 = Ratek[A],=overall reaction order=first order 4 2.00 x 10 -3 4.00 x 10 -3 8.00 x 10 -11

43 Concentration [A] x 10 -3 (in mol/L) 0.00 1.002.003.004.005.006.007.008.00 Reaction Rate x 10 -11 (in mol/L·s) 9.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 Reaction Rates V. Reaction Orders 10.00 -plot the data from the table on the graph below: zero-order reaction

44 Reaction Rates V. Reaction Orders -if a ________ with ____ or _____ _________ was ______________ __________ to be ______ ______ _______, the _____ _____ would be _____________ or ________________ reactiononemorereactants experimentallydeterminedsecond orderoverallratelaw Ratek[A] 2 =Ratek[A] 1 [B] 1 = -in ______ ______ reactions, the _____ _____ is _______________ or ___________, and the ______ of __ are_______ secondorderratelaw unitskL/mol·s AB products + Trial 1 Initial [B] (in M) 1.00 x 10 -3 Initial [A] (in M) 1.00 x 10 -3 Initial Rate (in mol/L·s) 0.500 x 10 -11 2 2.00 x 10 -3 1.00 x 10 -3 0.500 x 10 -11 3 2.00 x 10 -3 2.00 x 10 -11 Ratek[A] m [B] n = [B] = 2 m rate = 1 Ratek[A] m [B] 0 = [A] = 2 n rate = 4 Ratek[A] 2 [B] 0 = Ratek[A] 2,=overall reaction order=second order 4 2.00 x 10 -3 4.00 x 10 -3 8.00 x 10 -11 Ratek[A][B]=Ratek[A] 2 =

45 Concentration [A] x 10 -3 (in mol/L) 0.00 1.002.003.004.005.006.007.008.00 Reaction Rate x 10 -11 (in mol/L·s) 9.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 Reaction Rates V. Reaction Orders 10.00 -plot the data from the table on the graph below: zero-order reaction first-order reactionsecond-order reaction

46 Reaction Rates VI. Instantaneous Reaction Rates-while the ________ _________ _____ gives the ________ _____ over a period of _____, the ____________ _____ shows the ________ _____ at a ________ _____ averagereaction ratereactionrate time instantaneousrate reaction ratespecific time 1C 4 H 9 Cl1H 2 O+ 1C 4 H 9 OH1HCl+ Time, t (in s)[C 4 H 9 Cl] (in M)Average rate (in mol/L·s) 0.0 0.1000 50.00.09051.9 x 10 -4 100.00.08201.7 x 10 -4 150.00.0741 1.6 x 10 -4 200.00.06711.4 x 10 -4 300.00.05491.22 x 10 -4 400.00.04481.01 x 10 -4 500.0 0.03680.80 x 10 -4 800.0 0.0200 0.560 x 10 -4 Calculate w/Δquantity/Δt

47 Reaction Rates VI. Instantaneous Reaction Rates Time (in s) 0.00 0100200300400500600700800 [C 4 H 9 Cl (in M) 9001000 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 -plot the data from the table on the graph below: ΔtΔt Δ[C 4 H 9 Cl] Instantaneous rate = Δ[C 4 H 9 Cl] ΔtΔt Instantaneous rate = 0.03 mol/L 400 s Instantaneous rate = 0.8 x 10 -4 mol/L·s Instantaneous rate = rise Instantaneous rate = Slope of the tangent run

48 Reaction Rates VI. Instantaneous Reaction Rates-as the reaction proceeds, and the rate of _________ goes _____ as ________ of _________ are _________, the ______ of the _____ ________ to the _____ goes _____ as the ________ ____ goes _____ collisiondown particlesreactants consumedslope linetangentcurve downreactionrate down

49 Reaction Rates VI. Instantaneous Reaction Rates 2NO1H 2 +1N 2 O1H 2 O+ If the following equation is first order in H 2 and second order in NO with a rate constant of 2.90 x 10 2 L 2 /mol 2 ·s, what is the instantaneous rate when [NO] = 0.00200 M and [H 2 ] = 0.00400 M ? Ratek[NO] 2 [H 2 ] 1 = Rate=(2.90 x 10 2 L 2 /mol 2 ·s) Rate= (0.00400 mol/L) 1 (0.00200 mol/L) 2 4.64 x 10 -6 mol/L·s

50 Reaction Rates VI. Instantaneous Reaction Rates 2NO1H 2 +1N 2 O1H 2 O+ If the following equation is first order in H 2 and second order in NO with a rate constant of 2.90 x 10 2 L 2 /mol 2 ·s, what is the instantaneous rate when [NO] = 0.00500 M and [H 2 ] = 0.00200 M ? Ratek[NO] 2 [H 2 ] 1 = Rate=(2.90 x 10 2 L 2 /mol 2 ·s) Rate= (0.00200 mol/L) 1 (0.00500 mol/L) 2 1.45 x 10 -5 mol/L·s

51 Reaction Rates VI. Instantaneous Reaction Rates 2NO1H 2 +1N 2 O1H 2 O+ If the following equation is first order in H 2 and second order in NO with a rate constant of 2.90 x 10 2 L 2 /mol 2 ·s, what is the instantaneous rate when [NO] = 0.0100 M and [H 2 ] = 0.00125 M ? Ratek[NO] 2 [H 2 ] 1 = Rate=(2.90 x 10 2 L 2 /mol 2 ·s) Rate= (0.00125 mol/L) 1 (0.0100 mol/L) 2 3.62 x 10 -5 mol/L·s

52 Reaction Rates VI. Instantaneous Reaction Rates 2NO1H 2 +1N 2 O1H 2 O+ If the following equation is first order in H 2 and second order in NO with a rate constant of 2.90 x 10 2 L 2 /mol 2 ·s, what is the instantaneous rate when [NO] = 0.00446 M and [H 2 ] = 0.00282 M ? Ratek[NO] 2 [H 2 ] 1 = Rate=(2.90 x 10 2 L 2 /mol 2 ·s) Rate= (0.00282 mol/L) 1 (0.00446 mol/L) 2 1.63 x 10 -5 mol/L·s

53 Reaction Rates VI. Instantaneous Reaction Rates AB+products If the following equation is first order in A and second order in B with a specific rate constant of 4.75 x 10 -7 L 2 /mol 2 ·s, what is the instantaneous rate when [A] = 0.355 M and [B] = 0.0122 M ? Ratek[A] 1 [B] 2 = Rate=(4.75 x 10 -7 L 2 /mol 2 ·s) Rate= (0.0122 mol/L) 2 (0.355 mol/L) 1 2.51 x 10 -11 mol/L·s

54 Reaction Rates VII. Reaction Mechanisms-_____ chemical reactions consist of a ______ of ____ or _____ simpler _________ most seriesonemore reactions -a ________ ________ consists of ____ or _____ ___________ steps complexreactiontwo moreelementary -for example, the _____________ of ______, an _________ of ________, in the ______ _____ is a ________ ________ consisting of ______ ___________ _________ in the following ________ __________: decomposition ozoneallotropeoxygen ozonelayercomplex reactionthree elementaryreactions 1Cl1O 3 +1O 2 1ClO+ reactionmechanism 1O 3 1O 2 1O+ 1ClO1O+1O 2 1Cl+ 2O 3 3O 2

55 Reaction Rates VII. Reaction Mechanisms-because ____ is a _______ in the _____ __________ step and is _________ in the _____ ___________ step, it technically _________ the _____ of _________ without being _________ itself, and so is a _________ to the _____________ of ______ Cl 1Cl1O 3 +1O 2 1ClO+ 1O 3 1O 2 1O+ 1ClO1O+1O 2 1Cl+ 2O 3 3O 2 reactantfirst elementaryre-formed lastelementary increasesrate reactionconsumed catalyst decompositionozone -because both _____ and ___ are formed in ____ ____________ step of the _______ ________ and _________ in a __________ step, they are ___________ ClOO oneelementary complexreactionconsumed subsequentintermediates

56 Reaction Rates VII. Rate-Determining Step in a Complex Reaction Mechanism -the _______ elementary step in the ________ __________ of a ________ ________limits the ___________ ____ of the _______ _______, and so is called the ______________ ____ slowest reaction mechanism complexreaction instantaneousrate overallreaction rate-determiningstep 2NO1N 2 O 2 1N 2 O1H 2 O+ 1N 2 O1H 2 +1N 2 1H 2 O+ 1N 2 1H 2 + Reaction progress Energy 2NO + 2H 2 1N 2 O 2 + 2H 2 1N 2 O + 1H 2 O + 1H 2 2NO2H 2 +2H 2 O+ 1N 2 + 2H 2 O -the elementary step with the _______ __________ ______ is the _______, and so is the ______________ ____ highestactivation energyslowest rate-determiningstep Rate-Determining Step


Download ppt "Reaction Rates I. Expressing Reaction Rates-________ ____, or the ____ at which a _________ ________ occurs, is expressed in terms of ______ in ____________."

Similar presentations


Ads by Google