Ch.13 - Chemical KineticsWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds
Additional Problems
Which of the following statements is true regarding the forward reaction based on the reaction profile shown below? i. The reaction is endothermic. ii. Ea is approximately 2. iii. Ea is approximately +1. iv. The reaction is exothermic. A. i only B. iv only C. iii and iv D. ii and iv E. i and ii
Consider the figure below and choose the answer which identifies the rate limiting step for the forward reaction. A) R → I1 B) I1 → I2 C) I2 → P D) I1 → R E) P → I2
The potential energy profiles for three reactions are shown below. Which of the following is a  true statement? A) Endothermic rxns are always slower than exothermic rxns B) The faster the rate of a reaction the more exothermic it must be C) Ea of rxn 1 is 2 times that of rxn 3 D) For reaction 1, ΔHrxn = ‐70 k/mol E) The Ea for the reverse reaction of rxn 2 is Ea2 = +30 kj/mol  
A certain reaction has a ΔH = –75 kJ and an activation energy of 40 kJ. A catalyst is found that lowers the activation energy of the forward reaction by 15 kJ. What is the activation energy of the reverse reaction in the presence of this same catalyst? (A) 25 kJ (B) 60 kJ (C) 90 kJ (D) 100 kJ
Which line segment represents the activation energy for the reaction between  C and D to form A and B? (A) 1 → 4 (B) 2 → 3 (C) 2 → 4 (D) 3 → 4
Consider the potential energy diagram below: What is the change in enthalpy (ΔH ) for the reaction A → B? a. -350 kJ b. 100 kJ c. -100 kJ d. 350 kJ  
Four reactions are listed below with their energies indicated. Which of these reactions will have the fastest rate in the reverse? A. Rxn 1: ΔE = −15 kJ, Ea (forward) = 5 kJ B. Rxn 2: ΔE = +10 kJ, Ea (forward) = 15 kJ C. Rxn 3: ΔE = −10 kJ, Ea (forward) = 5 kJ D. Rxn 4: ΔE = 0 kJ, Ea (forward) = 15 kJ
The activation energy of a reaction is 7.5 kJ/mol and the change in enthalpy is −37.2 kJ/mol. What is the activation energy of the reverse reaction? a) 37.2 kJ/mol b) 7.5 kJ/mol c) 44.7 kJ/mol d) 29.7 kJ/mol e) The reverse does not occur and hence does not have an activation energy.
A chemical reaction has an activation energy in the forward direction of 158 kJ/mol and a ΔE°  of reaction -67 kJ/mol. Calculate the energy of activation for the reverse reaction. 
The reaction C4H10 → C2H6 + C2H4 has an activation energy (Ea) of 350 kJ/mol, and the Ea of the reverse reaction is 260 kJ/mol. Estimate ΔH, in kJ/mol, for the reaction as written above. A. -90 kJ/mol B. +90 kJ/mol C. 350 kJ/mol D. -610 kJ/mol E. +610 kJ/mol
With respect to the figure below, which choice correctly identifies all the numbered positions?  A. (1) catalyst, (2) intermediate, (3) activated complex, (4) product B. (1) reactants, (2) activated complex, (3) intermediate, (4) product C. (1) reactants, (2) activated complex, (3) catalyst, (4) product D. (1) reactants, (2) intermediate, (3) activated complex, (4) product E. (1) reactants, (2) intermediate, (3) activated complex, (4) catalyst 
For the chemical reaction system described by the diagram below, which statement is true  A. The forward reaction is endothermic. B. The activation energy for the forward reaction is greater than the activation energy for the reverse reaction. C. At equilibrium, the activation energy for the forward reaction is equal to the activation energy for the reverse reaction. D. The activation energy for the reverse reaction is greater than the activation energy for the forward reaction. E. The reverse reaction is exothermic. 
For the chemical reaction system described by the diagram below which statement is true?  If the Ea for the forward reaction is 25 kJ/mol and the enthalpy of reaction is -95 kJ/mol, what is Ea for the reverse reaction? A. 120 kJ/mol B. 70 kJ/mol C. 95 kJ/mol D. 25 kJ/mol E. -70 kJ/mol 
Label the multi-step reaction energy diagram below using the letters corresponding to the labels on the left. There are more labels than needed; each label can be used only once. A) Reaction intermediate B) Ea (step 2) C) Reactants D) Products E) Transition state F) Ea (step 1) G) Catalyst H) Equilibrium I) kf J) kr K) Reaction coordinate L) Energy
Which reaction coordinate diagram represents a reaction in which the activation energy, Ea, is 50 kJ•mol –1 and the ΔHrxn is –15 kJ•mol –1?
We can use a 2-D potential energy surface to depict the progress of a reaction. Given the following: a. The y-axis should be labeled as ___________ and the x-axis should be labeled as ____________ . b. From the labels A-G, _______ is/are the reactant(s), _______ is/are the product(s), _______ is/are the reaction intermediates, and _______ is/are the transition states (activated complexes). c. The reaction profile depicts _____ number of elementary steps. d. Step ____ is rate-limiting. e. The overall reaction is __________ (endothermic, exothermic). f. Write the equation for the overall reaction:  g. Explain how the addition of a catalyst will change the reaction depicted above. Will the rate law for the uncatalyzed and catalyzed reaction necessarily be the same? h. What is the difference between an activated complex and a reaction intermediate?
Energy is needed to overcome a barrier between initial and final states.If the barrier were lower than as shown in the figure, would the golfer have to hit the ball as hard?
The energy profile of a reaction, showing transition states and an intermediate.For this profile, is it easier for a molecule of the intermediate to convert to reactants or products?
Rate-determining steps in traffic flow on a toll road.For which of the two scenarios in the figure will one get from point 1 to point 3 most rapidly?
Suppose you could measure the rates for both the forward and reverse reactions of the process in the figure .In which direction would the rate be larger?
Energy profile for conversion of methyl isonitrile (H3CNC) to its isomer acetonitrile (H3CCN).How does the energy needed to overcome the energy barrier compare with the overall change in energy for this reaction?
Based on the reaction profile on the left , how many intermediates are formed in the reaction A ?
Based on the following reaction profile, how many intermediates are formed in the reaction AD?
Energy profiles for the uncatalyzed and bromide-catalyzed decomposition of H2O2.Where are the intermediates and transition states in this diagram?
On a reaction energy profile diagram, how is an intermediate represented?
The energy of activation for the decomposition of 2 mol of HI to H2 and I2 in the gas phase is 185 kJ. The heat of formation of HI(g) from H2 (g) and I2 (g) is -5.65 kJ/mol.Find the energy of activation for the reaction of 1 mol of H2 and 1 mol of I2 in the gas phase.
The gas-phase reaction Cl(g) + HBr(g)HCl(g) + Br(g) has an overall energy change of -66 kJ. The activation energy for the reaction is 7 kJ.What is the activation energy for the reverse reaction?
Label the following reaction coordinate diagram by matching between letters and numbers:
Which reaction coordinate diagram represents a reaction in which the activation energy, Ea, is 50 kj.mol-1 and the ΔHrxn is -15 kj. mol-1?
A reaction coordinate diagram is shown below for the reaction of A to form E. Answer the following questions. i) Identify the transition state(s)? ii) Which is the fastest reaction?  iii) Identify the rate limiting step? iv) Which compound is the most unstable?
Two reactions with different activation energies have the same rate at room temperature. Which statement correctly describes the rates of these two reactions at the same, higher temperature?(A) The reaction with the larger activation energy will be faster.(B) The reaction with the smaller activation energy will be faster.(C) The two reactions will continue to occur at the same rates.(D) A prediction cannot be made without an additional information
For the reaction in the below diagram, explain whether the forward or reverse reaction greater in rate A. The reverse reaction because its activation energy is lower B. The reverse reaction because its activation energy is higher C. The forward reaction because its activation energy is lower D. The forward reaction because its activation energy is higher
For the reaction X + Y → Z + R which arrow represents the activation energy of the forward reaction? 1. e 2. f 3. a 4. c 5. d 6. b
Please refer to the charts. a) What is the value of the activation energy of the uncatalyzed reaction? activation energy = ____________ b) What is the value of the enthalpy change of the uncatalyzed reaction? ΔH = ____________ c) What is the value of the activation energy of the uncatalyzed reaction in reverse? activation energy = ____________ d) What is the value of the enthalpy change of the uncatalyzed reaction in reverse? ΔH = ____________
Label the energy diagram for a two-step reaction.
If a reaction has ∆H = −125 kJ/mol and an activation energy of 72.8 kJ/mol, what is the activation energy for the reverse reaction?   a) −52.2 kJ/mol b) 72.8 kJ/mol c) 52.2 kJ/mol d) 198 kJ/mol e) 125 kJ/mol
Label the energy diagram (7 bins).
True or false: two reactions with identical activation energies will always have the same rate constant as long as the reactions are run at the same temperature.
Label this diagram (energy of activations, transition state, products, starting materials, and enthalpy change)
Please refer to the charts. a. What is the value of the activation energy of the uncatalyzed reaction? b. What is the value of the enthalpy change of the uncatalyzed reaction? c. What is the value of the activation energy of the uncatalyzed reaction in reverse? d. What is the value of the enthalpy change of the uncatalyzed reaction in reverse?
The activation energy for the reactionNO2(g) + CO(g) ⟶ NO(g) + CO2(g)is Ea = 100 kJ/mol and the change in enthalpy for the reaction is ΔH = -250 kJ/mol .What is the activation energy for the reverse reaction?
Based on the diagrams in Exercise 12.82, which of the reactions has the fastest rate? Which has the slowest rate?
Based on the diagrams in Exercise 12.83, which of the reactions has the fastest rate? Which has the slowest rate?
A chemical reaction is endothermic and has an activation energy that is twice the value of the enthalpy of the reaction. Draw a diagram depicting the energy of the reaction as it progresses. Label the position of the reactants and products and indicate the activation energy and enthalpy of reaction.
Is each of these statements true? If not, explain why.(j) Exothermic reactions are faster than endothermic reactions.
The following graph shows two different reaction pathways for the same overall reaction at the same temperature.Is each of the following statements true or false?(a) The rate is faster for the red path than for the blue path.(b) For both paths, the rate of the reverse reaction is slower than the rate of the forward reaction.(c) The energy change ΔE is the same for both paths.
Consider the following energy diagram showing the energy of a reaction as it progresses:How many elementary steps are involved in this reaction?
Consider the following energy diagram showing the energy of a reaction as it progresses:Which step is rate limiting?
Consider the following energy diagram showing the energy of a reaction as it progresses:Is the overall reaction endothermic or exothermic?
Suppose you could measure the rate constants for both the forward and reverse reactions of the process in Figure 14.16. In which direction would the rate constant be larger?
Suppose that the reaction A → products is exothermic and has an activation barrier of 75 kJ/mol. Draw an energy diagram showing the energy of the reaction as a function of the progress of the reaction.
The gas-phase reaction Cl(g) + HBr(g) → HCl(g) + Br(g) has an overall energy change of –66 kJ. The activation energy for the reaction is 7 kJ. Sketch the energy profile for the reaction.
You may want to reference (Pages 588 - 592) Section 14.5 while completing this problem.Based on their activation energies and energy changes and assuming that all collision factors are the same, rank the following reactions from slowest to fastest.(a) Ea = 45 kJ/mol; ΔE = –25 kJ/mol(b) Ea = 35 kJ/mol; ΔE = –10 kJ/mol(c) Ea = 55 kJ/mol; ΔE = 10 kJ/mol
Based on their activation energies and energy changes and assuming that all collision factors are the same, which of the following reactions would be fastest in the reverse direction?(a) Ea = 45 kJ/mol; ΔE = –25 kJ/mol(b) Ea = 35 kJ/mol; ΔE = –10 kJ/mol(c) Ea = 55 kJ/mol; ΔE = 10 kJ/mol
Based on their activation energies and energy changes and assuming that all collision factors are the same, which of the following reactions would be slowest in the reverse direction?(a) Ea = 45 kJ/mol; ΔE = –25 kJ/mol(b) Ea = 35 kJ/mol; ΔE = –10 kJ/mol(c) Ea = 55 kJ/mol; ΔE = 10 kJ/mol
Consider the following reaction energy diagram:(a) How many elementary steps are in the reaction mechanism?
Consider the following reaction energy diagram:(b) Which step is rate-limiting?
Consider the following reaction energy diagram:(c) Is the overall reaction exothermic or endothermic?
Based on the following reaction profile, how many transition states are formed in the reaction A → C?
Based on the following reaction profile, which step is the fastest?
What is the activation energy of a reaction, and how is this energy related to the activated complex of the reaction?
For the reaction A → C, is ΔE positive, negative, or zero?
Based on the following reaction profile, how many transition states are there?
Based on the following reaction profile, which step is the fastest?
For the reaction A → D, is ΔE positive, negative, or zero?
Consider the following energy profile.How many elementary reactions are in the reaction mechanism?
Consider the following energy profile.How many intermediates are formed in the reaction?
Consider the following energy profile.Which step is rate limiting?
Consider the following energy profile.For the overall reaction, is E positive, negative, or zero?
The rate law for the reactionNO2(g) + CO(g) ⟶NO(g) + CO2(g)is rate = k[NO2]2; one possible mechanism is shown in Section 16.6.(a) Draw a reaction energy diagram for that mechanism, given that ΔH°overall = -226 kJ/mol.
The following diagram shows the energy of a reaction as the reaction progresses. Label each of the following in the diagram:
The following diagram shows the reaction profile of a reaction.Label the components indicated by the boxes.
For the following reaction profile, indicateb. the activation energy.
For the following reaction profile, indicatec. DE for the reaction.
Draw a rough sketch of the energy profile for each of the following cases:b. ΔE = -10 kJ/mol, Ea = 50 kJ/mol
Draw a graph showing the reaction pathway for an overall exothermic reaction with two intermediates that are produced at different rates. On your graph indicate the reactants, products, intermediates, transition states, and activation energies.
Draw a rough sketch of the energy profile for each of the following cases:c. ΔE = -50 kJ/mol, Ea = 50 kJ/mol
Consider the following energy diagram showing the energy of a reaction as it progresses:Label the reactants, products, and intermediates.
For the following reaction profile, indicatea. the positions of reactants and products.
Draw a rough sketch of the energy profile for each of the following cases:a. ΔE = +10 kJ/mol, Ea = 25 kJ/mol
For the reaction ABC + D ⇌ AB + CD, ΔH°rxn = −55 kJ/mol and Ea(fwd) = 215 kJ/mol. Assuming a one-step reaction,(a) draw a reaction energy diagram; 
For the reaction A2 + B2 ⟶2AB, Ea(fwd) = 125 kJ/mol and Ea(rev) = 85 kJ/mol. Assuming the reaction occurs in one step(a) draw a reaction energy diagram; 
Aqua regia, a mixture of HCl and HNO3, has been used since alchemical times to dissolve many metals, including gold.Its orange color is due to the presence of nitrosyl chloride. Consider this one-step reaction for the formation of this compound:NO(g) + Cl2(g) ⟶NOCl(g) + Cl(g)                    ΔH° = 83 kJ(a) Draw a reaction energy diagram, given Ea(fwd) = 86 kJ/mol.
The gas-phase reaction Cl(g) + HBr(g) → HCl(g) + Br(g) has an overall energy change of –66 kJ. The activation energy for the reaction is 7 kJ. Sketch the energy profile for the reaction and label Ea and ΔE.
For each of the following reaction diagrams, estimate the activation energy (Ea ) of the reaction:
For each of the following reaction diagrams, estimate the activation energy (Ea ) of the reaction:
For each of the following reaction diagrams, estimate the activation energy (Ea ) of the reaction:
For each of the following reaction diagrams, estimate the activation energy (Ea ) of the reaction:
For the elementary process N2O5 (g) → NO2 (g) + NO3 (g) the activation energy (Ea) and overall E are 154 kJ/mol, and 136 kJ/mol, respectively.What is the activation energy for the reverse reaction?
The activation energy for the reactionNO2 (g) + CO (g) → NO (g) + CO2 (g)is 125 kJ/mol, and ΔE for the reaction is -216 kJ/mol. What is the activation energy for the reverse reaction [NO (g) + CO2 (g) → NO2 (g) + CO(g)]?
The activation energy for some reaction X2 (g) + Y2 (g) → 2XY (g)is 167 kJ/mol, and ΔE for the reaction is 128 kJ/mol. What is the activation energy for the decomposition of XY?
For the reaction ABC + D ⇌ AB + CD, ΔH°rxn = −55 kJ/mol and Ea(fwd) = 215 kJ/mol. Assuming a one-step reaction,(a) draw a reaction energy diagram;(b) calculate Ea(rev);
For the reaction A2 + B2 ⟶2AB, Ea(fwd) = 125 kJ/mol and Ea(rev) = 85 kJ/mol. Assuming the reaction occurs in one step(a) draw a reaction energy diagram;(b) calculate ΔH°rxn; and
i) What is the heat of reaction for Reaction A?  ii) What is the activation energy for Reaction A?
Aqua regia, a mixture of HCl and HNO3, has been used since alchemical times to dissolve many metals, including gold.Its orange color is due to the presence of nitrosyl chloride. Consider this one-step reaction for the formation of this compound:NO(g) + Cl2(g) ⟶NOCl(g) + Cl(g)                    ΔH° = 83 kJ(a) Draw a reaction energy diagram, given Ea(fwd) = 86 kJ/mol.(b) Calculate Ea(rev).
Part AWhat is the value of the activation energy of the uncatalyzed reaction?Express your answer to three significant figures and include the appropriate units.Part BWhat is the value of the enthalpy change of the uncatalyzed reaction?Express your answer to three significant figures and include the appropriate units.Part CWhat is the value of the activation energy of the uncatalyzed reaction in reverse?Part DWhat is the value of the enthalpy change of the uncatalyzed reaction in reverse?Express your answer to three significant figures and include the appropriate units.
What is the heat of reaction for Reaction A? What is the heat of reaction for Reaction B? What is the activation energy for Reaction A? What is the activation energy for Reaction B?
The diagram represents a spontaneous reaction. Use the diagram to answer the questions below.a. Is the reaction endothermic or exothermic?b. What is the activation energy of the reaction?