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Reaction Rates

Reaction Rates. I. Expressing Reaction Rates. -________ ____, or the ____ at which a _________ ________ occurs, is expressed in terms of ______ in ____________ of a ________ or _______ per unit ____. reaction. rate. rate. chemical. reaction. change. concentration. reactant.

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Reaction Rates

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  1. Reaction Rates I. Expressing Reaction Rates -________ ____, or the ____ at which a _________ ________ occurs, is expressed in terms of ______ in ____________ of a ________ or _______ per unit ____ reaction rate rate chemical reaction change concentration reactant product time What is the reaction rate of the following reaction, in moles/liter·second, if the concentration of NO is 0.000 moles/liter at t1 = 0.00 seconds and 0.010 moles/liter 2 seconds after the reaction begins? 1CO (g) + 1NO2(g) 1CO2(g) + 1NO(g) Δquantity Average reaction rate = Δt (t2 – t1) 0.010 M – 0.000 M Average reaction rate = 2.00 s – 0.00 s Average reaction rate = 0.0050 mol/L·s

  2. Reaction Rates I. Expressing Reaction Rates -________ ____ can be expressed as the ____ at which a ________ is produced or the ____ at which a ________ is consumed reaction rate rate product rate reactant What is the reaction rate of the following reaction, in moles/liter·second, if the concentration of C4H9Cl is 0.220M at t1 = 0.00 seconds and 0.100 M 4.00 seconds after the reaction begins? 1C4H9Cl + 1H2O 1C4H9OH + 1HCl brackets indicate the concentration of butyl chloride Δquantity Average reaction rate = Δt 0.100 M – 0.220 M Average reaction rate = 4.00 s – 0.00 s Average reaction rate = 0.0300 mol/L·s

  3. Reaction Rates I. Expressing Reaction Rates What is the reaction rate of the following reaction, in moles/liter·second, expressed in moles of H2 consumed, if the concentration of H2 is 0.030M at t1 = 0.00 seconds and 0.020M 4.00 seconds after the reaction begins? 1H2 + 1Cl2 2HCl Δquantity Average reaction rate = Δt 0.020 M – 0.030 M Average reaction rate = 4.00 s – 0.00 s Average reaction rate = 0.0025 mol/L·s 2 moles HCl 0.010 moles H2 x ______________ = 0.020 moles HCl 1 mole H2

  4. Reaction Rates I. Expressing Reaction Rates 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 t1 = 0.00 seconds and 0.020M 4.00 seconds after the reaction begins? 1H2 + 1Cl2 2HCl Δquantity Average reaction rate = Δt 0.020M – 0.000M Average reaction rate = 4.00 s – 0.00 s Average reaction rate = 0.0050 mol/L·s

  5. Reaction Rates I. Expressing Reaction Rates What is the reaction rate of the following reaction, in moles/liter·minute, expressed in moles of H2O2 consumed, if the concentration of H2O2 is 2.50M at t1 = 0.00 minutes and 2.12M 2.00 minutes after the reaction begins? 2H2O2 1O2 + 2H2O Δquantity Average reaction rate = Δt 2.12M – 2.50M Average reaction rate = 2.00 min – 0.00 min Average reaction rate = 0.19 mol/L·min

  6. Reaction Rates I. Expressing Reaction Rates What is the reaction rate of the following reaction, in moles/liter·minute, expressed in moles of O2 produced, if the concentration of H2O2 is 1.82M at t1 = 0.00 minutes and 1.48M 5.00 minutes after the reaction begins? 2H2O2 1O2 + 2H2O 1 mole O2 0.34 moles H2O2 x ______________ = 0.17 mole O2 2 mole H2O2 Δquantity Average reaction rate = Δt 0.17M – 0.00M Average reaction rate = 5.00 min – 0.00 min Average reaction rate = 0.034 mol/L·min

  7. Reaction Rates II. The Collision Theory -the _________ ______ states that, in order for a ________ ________ to take place, the ______, ____, or _________ must _______ in order to _____ Collision Theory chemical reaction atoms ions molecules collide react 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?

  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 Theory Cl2 H2 collide react Carbon monoxide Nitrogen dioxide small fraction collisions reactions Why? 1CO (g) + 1NO2(g) 1CO2(g) + 1NO(g) 1Cl2 + 1H2 2HCl

  9. Reaction Rates II. The Collision Theory Collision Collision CO NO2 CO NO2 Rebound Rebound Incorrect orientation Incorrect orientation NO2 CO NO2 CO

  10. Reaction Rates II. The Collision Theory Collision Correct orientation CO NO2 Activated complex CO2 NO Collision Orientation Always Correct Cl2 H2

  11. Reaction Rates II. The Collision Theory -according to the _________ ______, the _________ of ________ _________ must __ _______, __ _______ with the correct ___________, and __ _______ with sufficient ______ to form the _________ _______ Collision Theory particles reacting substances 1. collide 2. collide orientation 3. collide energy activation complex Collision CO NO2 Rebound Insufficient energy CO NO2

  12. Reaction Rates II. The Collision Theory -the minimum amount of ______ that reacting particles must have to form the ________ _______ is called the ________ ______, or ___ energy activation complex 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 activation energy Ea -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 ______ high activation energy few collisions energy activation complex low activation complex activation energy many collisions energy activation energy activation complex reaction rate higher products 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 reactants

  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 __________ activation energy reactants products lower energy state reactants energy released reaction reaction exothermic -if the ________ end up lying at a _______ ______ _____ than the _________, then ______ is ________ by the _______, and the ________ is __________ products higher energy state reactants energy absorbed reaction reaction 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 reactive nature reactants 1Ca (s) + 2H2O(l) 1Ca(OH)2(aq) + 1H2(g) Calcium reacts with cold water to produce Calcium hydroxide and Hydrogen gas 2Na (s) + 2H2O(l) 2NaOH(aq) + 1H2(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 ______ ___ concentration reactants increased speed up collision chemical -since _________ is necessary for _________ _________ to take place, __________ the ____________ of the ________ _________ increases the likelihood that the _________ of one ________ will _______ with the _________ of the other _________ reactions increasing concentration reacting particles particles reactant collide particles reactant 4Fe + 3O2 2Fe2O3 +

  16. Reaction Rates III. Factors Affecting Reaction Rates B. Concentration 4Fe + 3O2 2Fe2O3 + 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 surface area same mass increased reducing size reaction rate increase surface area particles reactant collide more reactant 4Fe + 3O2 2Fe2O3 +

  18. Reaction Rates III. Factors Affecting Reaction Rates D. Temperature increasing temperature -__________ the ___________ at which a _______ occurs _________ the _______ ____ reaction increases reaction rate increasing temperature increases -__________ the ___________ _________ the average _______ _____ of the _________ that make up a substance, causing the ________ to _______ more ___________ 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 kinetic energy particles particles collide frequently 40 35 Temperature (in K) Relative Reaction Rate 30 25 290 2 20 Relative Reaction Rate 310 8 15 10 320 16 5 330 32 0 280 290 300 310 320 330 Temperature (in K)

  19. Reaction Rates III. Factors Affecting Reaction Rates increasing temperature increases -__________ the ___________ also ________ the ____ of _______ by _________ the _______ of _________ with _________ ________ ______ to cause a _______ D. Temperature rate reaction increasing number particles sufficient collision energy reaction -__________ the ___________, then, _______ the _______ ____ by _________ the _________ _________ and the _________ ______ increasing temperature increases reaction rate increasing collision frequency collision energy

  20. Reaction Rates III. Factors Affecting Reaction Rates E. Catalysts -_________ are __________ that _______ the _____ of ________ without being _________ by the ________ catalysts substances increase rate reaction consumed Substrate (Reactant) reaction enzymes biological catalysts -________ are _________ ________ which cause _________ to happen or happen ______ without _______ the __________, which could ________ living things by __________ their ________ reactions faster raising temperature damage Enzyme denaturing proteins -________ increase ________ ____ by ________ the _________ ______ for a _________, so that ________ that had ____________ energy before now have _________ energy to ______ catalysts reaction rate lowering activation energy reaction particles insufficient sufficient react -_________ make reactions _____ likely to _______ by ________ the __________ ______ inhibitors less proceed raising activation energy

  21. Reaction Rates III. Factors Affecting Reaction Rates 1. Hypothesis: What is the effect of temperature on the rate of reaction? 2. Prediction: 3. Gather Data: A. Safety: 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. 2. Measure and record the mass of 1 piece of effervescent tablet.

  22. Reaction Rates III. Factors Affecting Reaction Rates 3. Gather Data: B. Procedure: 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. 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. 1H3C6H5O7 + 1C4H8O4 + 4NaHCO3 Citric acid Acetylsalicylic acid Sodium bicarbonate 1NaC4H7O4 + 1Na3C6H5O7 + 4H2O + 4CO2 Sodium acetyl salicylate Sodium citrate Water Carbon dioxide

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

  24. Reaction Rates III. Factors Affecting Reaction Rates 4. Analyze Data: B. Graph the temperature versus the reaction rate on the following graph, and draw a best-fit curve for the data 0.10 0.09 0.08 0.07 0.06 Relative Reaction Rate (in g/s) 0.05 0.04 0.03 0.02 0.01 0.00 0 10 20 30 40 50 60 70 80 90 100 Temperature (in °C)

  25. Reaction Rates III. Factors Affecting Reaction Rates 4. Analyze Data: 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. Reaction Rates III. Factors Affecting Reaction Rates 5. Draw Conclusions: using the analysis of the data, answer the question of the hypothesis ________________________________________________________________________________

  27. Reaction Rates IV. Reaction Rate Laws -when we divide the ________ in _______ ____________, __________ by the _______ in _____, ____, we get an ________ ________ _____ change molar concentration (Δquantity) change time (Δt) average reaction rate -chemical reactions tend to _____ _____ as ________ are _________, because in order for a reaction to proceed, _________ must _______, and as _________ are _________ there are ______ ________ left to _______ slow down reactants consumed particles collide reactants consumed fewer particles collide 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

  28. Reaction Rates IV. Reaction Rate Laws -_____ ______ ________ the results of the _________ _______ in terms of a ____________ ___________ between the _____ of a _________ ________ and the ________ _____________ rate laws quantify collision theory mathematical relationship rate chemical reaction reactant concentration -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 → B one activated complex reactants products rate law Rate k [A] [A] concentration reactant A k experimentally determined specific rate constant reaction conditions temperature -the ________ _____, then, is _________ _____________ to the _____________ reaction rate directly proportional concentration

  29. Reaction Rates V. Reaction Orders -in the reaction __ ___ __, the _____ = __ ___, and it is understood that ____ means the same as ____, and the _________ __ is the ________ ______ A → B Rate k [A] [A] [A]1 exponent 1 reaction order 2H2O2 2H2O + 1O2 -the _____ ____ for the _____________ of _____ is _____ = __ ______, and the ________ is said to be _____ _____ in _____ rate law decomposition H2O2 Rate k [H2O2]1 reaction first order H2O2 A + B products -for _________ with _____ than _____ _______, the _____ ____ is _____ = __ ____ ____ where __ is the _______ _____ for __ and __ is the _______ _____ for __ reactions more one reactant rate law Rate k [A]m [B]n m reaction order A n reaction order B

  30. Reaction Rates V. Reaction Orders -for the ________ that has the _____ ____ _________________, the reaction is described as _______ _____ in ___, _____ _____ in ___, and _____ _____ overall reaction rate law Rate = k [NO]2 [H2]1 second order NO first order H2 third order -an ___________ _______ of evaluating ________ ______is the _______ of _______ ______, in which the ______________ of the _________ are _______ and the effect on the ________ _____ is observed experimental method reaction order method initial rates concentrations reactants varied reaction rate A + B products Initial [A] (in M) Initial Rate (in mol/L·s) Trial Initial [B] (in M) 0.100 1 0.100 2.00 x 10-3 0.200 2 0.100 4.00 x 10-3 0.200 3 0.200 16.00 x 10-3

  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 ___ = __, __ = __ rate law Rate = k [A]m [B]n [B] reaction rate doubled [A] doubled reaction order m 1 2m 2 m 1 [B] -in Trial 3 compared to Trial 2, ____ is _______, and the _______ ____ ___________, so the ________ ______ __ must equal __, or ___ = __, and the _______ _____ ____ is _________________ and the _______ ________ ______ is ______ _____ _______ doubled reaction rate quadruples reaction order n 2 overall rate law 2n 4 Rate = k [A]1 [B]2 overall reaction order third order (2 + 1)

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

  33. Reaction Rates V. Reaction Orders Given the following experimental data, use the method of initial rates to determine the rate law for the reaction and the overall reaction order. CH3CHO CH4 + CO Initial Rate (in mol/L·s) Initial [CH3CHO] (in M) Trial 2.00 x 10-3 2.70 x 10-11 1 [CH3CHO] = 2m rate = 4 2 4.00 x 10-3 10.8 x 10-11 rate = 4 [CH3CHO] = 2m 3 8.00 x 10-3 43.2 x 10-11 Rate = k [CH3CHO]m Rate = k [CH3CHO]2, overall reaction order = second order

  34. Reaction Rates V. Reaction Orders 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. 2NO + Cl2 2NOCl Initial [NO] (in M) Initial Rate (in mol/L·min) Trial Initial [Cl2] (in M) 0.50 1 0.50 1.90 x 10-2 [NO] = 2m rate = 4 1.00 2 0.50 7.60 x 10-2 [Cl2] = 2n rate = 2 1.00 15.20 x 10-2 3 1.00 Rate = k [NO]m [Cl2]n Rate = k [NO]2 [Cl2]n (or 0.15 L2/mol2·min) Rate = k [NO]2 [Cl2]1 (or 0.152 L2/mol2·min) overall reaction order = third order, k = 0.16 L2/mol2·min

  35. Reaction Rates V. Reaction Orders 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. 2ClO2(aq) + 2OH-(aq) 1ClO3- + 1ClO2- + 1H2O(1) Initial [ClO2] (in M) Initial Rate (in mol/L·min) Trial Initial [OH-] (in M) 0.0500 1 0.200 6.90 [ClO2] = 2m rate = 4 0.100 2 0.200 27.6 [OH-] = ½n rate = ½ 0.100 13.8 3 0.100 Rate = k [ClO2]m [OH-]n Rate = k [ClO2]2 [OH-]n Rate = k [ClO2]2 [OH-]1 overall reaction order = third order, k = 1.38 x 104 L2/mol2·min

  36. Reaction Rates V. Reaction Orders 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. A + B 2C Initial [A] (in M) Initial Rate (in mol/L·s) Trial Initial [B] (in M) 0.010 1 0.010 0.0060 [A] = 2m rate = 4 0.020 2 0.010 0.0240 [B] = 2n rate = 4 0.020 0.0960 3 0.020 Rate = k [A]m [B]n Rate = k [A]2 [B]n Rate = k [A]2 [B]2 overall reaction order = fourth order, k = 6.0 x 105 L3/mol3·s

  37. Reaction Rates V. Reaction Orders 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. A + B products Initial [A] (in M) Initial Rate (in mol/L·hr) Trial Initial [B] (in M) 0.010 1 0.020 0.020 [A] = 1½m rate = 1½ 0.015 2 0.020 0.030 [B] = 2n rate = 8 0.015 0.240 3 0.040 Rate = k [A]m [B]n Rate = k [A]1 [B]n Rate = k [A]1 [B]3 overall reaction order = fourth order, k = 2.5 x 105 L3/mol3·hr

  38. Reaction Rates V. Reaction Orders 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? Initial [A] (in M) Initial Rate (in mol/L·s) Trial Initial [B] (in M) 1.0 1 0.20 0.10 2.0 2 0.60 ? Rate = k [A]m [B]n Rate = k [A]1 [B]2 0.10 mol/L·s = k (1.0 mol/L)1 (0.20 mol/L)2 k = 2.5 L2/mol2·s Rate = k [A]1 [B]2 Rate = (2.5 L2/mol2·s) (2.0 mol/L)1 (0.60 mol/L)2 = 1.8 mol/L·s

  39. Reaction Rates V. Reaction Orders -most _________ _________ obey ____ of ______ _____ ______: _____ _____, _____ _____, or _______ _____, and the ______ of the _________ _____ ________, __, vary with the ______ of the ________ chemical reactions one three rate laws zero order first order second order units specific rate constant k order reaction reaction one more reactants -if a ________ with ____ or _____ _________ was ______________ __________ to be _____ ______ _______, the _____ _____ would be _____________ or ________________ experimentally determined zero order overall rate law Rate = k [A]0 Rate = k [A]0 [B]0 -in ______ ______ reactions, the _____ _____ is _________, and the ______ of __ are ________ zero order rate law Rate = k units k mol/L·s

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

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

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

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

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

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

  46. Reaction Rates VI. Instantaneous Reaction Rates -while the ________ _________ _____ gives the ________ _____ over a period of _____, the ____________ _____ shows the ________ _____ at a ________ _____ average reaction rate reaction rate time instantaneous rate Time, t (in s) [C4H9Cl] (in M) Average rate (in mol/L·s) reaction Calculate w/Δquantity/Δt 0.1000 rate specific 0.0 time 50.0 0.0905 1.9 x 10-4 1C4H9Cl + 1H2O 100.0 0.0820 1.7 x 10-4 1.6 x 10-4 150.0 0.0741 200.0 0.0671 1.4 x 10-4 300.0 0.0549 1.22 x 10-4 1C4H9OH + 1HCl 400.0 0.0448 1.01 x 10-4 500.0 0.0368 0.80 x 10-4 800.0 0.560 x 10-4 0.0200

  47. Reaction Rates VI. Instantaneous Reaction Rates -plot the data from the table on the graph below: 0.10 0.09 0.08 Instantaneous rate Slope of the tangent = 0.07 0.06 Instantaneous rate [C4H9Cl (in M) rise = 0.05 run 0.04 Δ[C4H9Cl] Instantaneous rate Δ[C4H9Cl] = 0.03 Δt 0.02 Δt Instantaneous rate 0.03 mol/L = 0.01 400 s 0.00 Instantaneous rate 0 100 200 300 400 500 600 700 800 900 1000 0.8 x 10-4 mol/L·s = Time (in s)

  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 _____ collision down particles reactants consumed slope line tangent curve down reaction rate down

  49. Reaction Rates VI. Instantaneous Reaction Rates If the following equation is first order in H2 and second order in NO with a rate constant of 2.90 x 102 L2/mol2·s, what is the instantaneous rate when [NO] = 0.00200 M and [H2] = 0.00400 M ? 2NO + 1H2 1N2O + 1H2O Rate = k [NO]2 [H2]1 Rate = (2.90 x 102 L2/mol2·s) (0.00200 mol/L)2 (0.00400mol/L)1 Rate = 4.64 x 10-6 mol/L·s

  50. Reaction Rates VI. Instantaneous Reaction Rates If the following equation is first order in H2 and second order in NO with a rate constant of 2.90 x 102 L2/mol2·s, what is the instantaneous rate when [NO] = 0.00500 M and [H2] = 0.00200 M ? 2NO + 1H2 1N2O + 1H2O Rate = k [NO]2 [H2]1 Rate = (2.90 x 102 L2/mol2·s) (0.00500 mol/L)2 (0.00200mol/L)1 Rate = 1.45 x 10-5 mol/L·s

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