Reaction Kinetics Multiple Choiceabbycloud.ca/andrewpenner/wp-content/uploads/2015/11/ReactKinM… · The rate of consumption of Ca is A. 0.00208 mol/min B. 0.0833 mol/min C. 0.125

Reaction Kinetics Multiple Choice

January 1999 1. Consider the reaction:

Ca (s) + 2H2O (l) � Ca(OH)2 (aq) + H2 (g)

At a certain temperature, 2.50 g Ca reacts completely in 30.0 seconds.

The rate of consumption of Ca is

A. 0.00208 mol/min

B. 0.0833 mol/min

C. 0.125 mol/min

D. 5.00 mol/min

2. The minimum amount of energy required to overcome the energy barrier in a chemical

reaction is the

A. heat of reaction.

B. activation energy.

C. KE of the reactants.

D. enthalpy of the products.

3. An activated complex is a chemical species that is

A. stable and has low PE.

B. stable and has high PE.

C. unstable and has low PE.

D. unstable and has high PE.

4. A certain reaction is able to proceed by various mechanisms. Each mechanism has a

different Ea and results in a different overall rate. Which of the following best describes

the relationship between the Ea values and the rates?

5. Consider the following PE diagram:

The forward reaction can be described as

6. Consider the following reaction mechanism:

In this reaction, H2 is a

A. product.

B. catalyst.

C. reactant.

D. reaction intermediate.

April 1999

1. The slowest of the following reactions is

A. Ag+ (aq) + Cl

- (aq) � AgCl (s)

B. H3O+ (aq) + OH

- (aq) � 2H2O (l)

C. 3Ba 2+

(aq) + 2PO43-

(aq) � Ba3(PO4)2 (s)

D. Cu(s) + 2Ag+ (aq) � Cu

2+ (aq) + 2Ag(s)

2. The rate of a chemical reaction is equal to the slope of a graph with the axes labeled

3. Consider the following reaction:

CH4 (g) + 2O2 (g) � CO2 (g) + 2H2O (g) + heat

The diagram which represents the relationship between rate and temperature is:

4. Which of the following describes the energy of colliding particles as reacting

molecules approach each other?

5. The average kinetic energy of colliding particles can be increased by

A. adding a catalyst.

B. increasing pressure.

C. increasing temperature.

D. increasing reactant concentration.

6. A substance that increases the rate of a chemical reaction and may be recovered

unchanged at the end of the reaction is a(n)

A. product.

B. catalyst.

C. activated complex.

D. reaction intermediate.

7. Consider the following PE diagram for a reversible reaction:

June 1999

1. Which of the following can be used to represent the rate of a reaction?


2H2O2 (l) � 2H2O (l) + O2 (g)

Which graph shows the relationship between rate of consumption of H2O2 and time?


Mg(s) + 2HCl (aq) � H2(g) + MgCl2(aq)

The rate of this reaction increases when more magnesium is added. This change is caused

by the

A. addition of a catalyst.

B. increase in surface area.

C. change in nature of the reactants.

D. increase in concentration of reactants.


5. Which graph shows the relationship between activation energy (Ea) and temperature?

6. A catalyst changes the rate of a reaction by

A. changing ∆H.

B. increasing the temperature.

C. decreasing the energy of the products.

D. providing an alternate reaction mechanism.

August 1999

1. At room temperature, which of the following reactions is fastest?

A. 2H2(g) + O2 (g) � 2H2O(g) B. Pb2+ (aq) + 2I- (aq) � PbI2(s) C. 4Fe(s) + 3O2(g) � 2Fe2O3(s) D. Cu(s) + 2Ag+ (aq) � Cu2+

(aq) + 2Ag(s)


CH4 (g) + 2O2 (g) � CO2 (g) + 2H2O (g)

At a certain temperature, 1.0 mol CH4 is consumed in 4.0 minutes.

The rate of production of H2O is

A. 0.25 mol/min

B. 0.50 mol/min

C. 2.0 mol/min

D. 8.0 mol/min

3. Consider the following reaction in a closed system:

H2(g) + I2(g) 2HI(g)

Which of the following will cause the rate of the forward reaction to decrease?

A. H2 is added.

B. A catalyst is added.

C. The volume is increased.

D. The temperature is increased.

4. The changes in PE and KE, as reactant molecules approach each other, can be

represented by


Which of the following describes this reaction?

6. A chemical reaction that gives off energy is

A. exothermic and ∆H is positive.

B. exothermic and ∆H is negative.

C. endothermic and ∆H is positive.

D. endothermic and ∆H is negative.

January 2000

1. Which of the following is most likely to have the greatest reaction rate at room

temperature?

A. 2H2(g) + O2(g) � 2H2O(l)

B. 2Ag+ (aq) + CrO4

2- (aq) � Ag2CrO4(s)

C. Pb(s) + 2HCl(aq) � PbCl2(aq) + H2(g)

D. CH4 (g) + 2O2(g) � CO2(g) + 2H2O(g)

2. Consider the following reaction involving 1 0. g of powdered zinc:

Zn (s) + 2HCl (aq) � ZnCl2 (aq) + H2 (g)

The rates, in order of fastest to slowest, are

A. 1, 2, 3

B. 2, 1, 3

C. 3, 1, 2

D. 3, 2, 1

3. Activation energy can be described as the

A. energy of motion.

B. energy of the activated complex.

C. energy difference between the reactants and the products.

D. energy difference between the reactants and the activated complex.

4. Consider the following potential energy diagram for a reversible reaction:

Which of the following describes the system above?

5. Increasing the temperature of a reaction increases the reaction rate by

I. increasing frequency of collisions

II. increasing the kinetic energy of collision

III. decreasing the potential energy of collision

A. I only.

B. I and II only.

C. II and III only.

D. I, II and III.

6. What effect does a catalyst have on a reaction?

A. It changes the ∆H of a reaction.

B. It increases the kinetic energy of the reactants.

C. It decreases the potential energy of the products.

D. It provides a reaction mechanism with a lower activation energy.

April 2000

1. At 25°C, which of the following reactions is fastest?

A. H2(g) + I2(g) � 2HI(g)

B. Ag+ (aq) + I

-(aq) � AgI(s)

C. C6H12O6 (s) + 6O2(g) � 6CO2(g) + 6H2O(g)

D. 5C2O42-

(aq) + 2MnO4- (aq) + 16H

+ (aq) � 16CO2 (g) + 2Mn

2+ (aq) + 8H2O(l)

2. Consider the graph for the following reaction:

CaCO3(s) + 2HCl (aq) � CaCl2(aq) + CO2 (g) + H2O(l)

The average rate of reaction is greatest in the time interval

A. 0 - 1 minute.

B. 0 - 2 minutes.

C. 0 - 3 minutes.

D. 0 - 4 minutes. 3. Which of the following changes will increase the average kinetic energy of reactant

molecules?

A. adding a catalyst

B. increasing the temperature

C. increasing the surface area

D. increasing the concentration

4. Consider the following potential energy diagram:

Which of the following represents the heat of reaction, ∆H, for the forward reaction?

A. I

B. II

C. III

D. IV

5. When a catalyst is added to a reaction

I. the heat of reaction increases

II. a new mechanism is provided

III. the equilibrium constant increases

A. II only

B. I and II only

C. II and III only

D. I, II and III

6. Consider the following mechanism for a reaction:

Step 1. HBr + O2 � HOOBr

Step 2. HBr + HOOBr � 2HOBr

Step 3. 2HBr + 2HOBr � 2H2O + 2Br2

Which of the following statements is correct?

A. Br2 is a reactant.

B. HBr is a product.

C. HOBr is a catalyst.

D. HOOBr is a reaction intermediate.

June 2000

1. Which of the following reactions will be slowest at 25°C?

A. Cu (s) + S(s) � CuS(s)

B. H+ (aq) + OH

- (aq) � H2O(l)

C. Pb 2+

(aq) + 2Cl- (aq) � PbCl2(s)

D. 2NaOCl(aq) � 2NaCl (aq) + O2(g)

2. Which of the following could be used as the units for rate of a reaction?

I. mL/s

II. g/min

III. M/min

A. I only.

B. I and II only.

C. II and III only.

D. I, II and III.


Zn (s) + 2HCl (aq) � ZnCl2(aq) + H2(g)

A graph of concentration of HCl vs time could be represented by

4. Consider the following experiments, each involving equal masses of zinc and 10.0 mL

of acid:

The rate of reaction in order from fastest to slowest is

A. I > II > III

B. II > I > III

C. III > I > II

D. III > II > I

5. What happens to the energy of reactant molecules as they approach one another?


Step 1. ClO- + H2O� HClO + OH

-

Step 2. I- + HClO� HIO + Cl

-

Step 3. HIO + OH- � IO

- + H2O

The catalyst is

A. IO-

B. H2O

C. ClO-

D. ClOH

August 2000


N2 (g) + 3H2 (g) � 2NH3 (g)

If the rate of formation of NH3 is 4.0 x 10-4

mol/s, then the rate of consumption of H2 is

A. 2.0 X 10-4

mol/s

B. 4.0 X 10–4

mol/s

C. 6.0 X 10–4

mol/s

D. 1.2 X 10–3

mol/s


Zn (s) + 2HCl (aq) � ZnCl2 (aq) + H2(g)

Which of the following instruments could be used to monitor the rate of the

reaction in an open system?

I. Balance

II. Pressure gauge

III. pH meter

A. I and II only.

B. I and III only.

C. II and III only.

D. I, II and III.

3. Which of the following changes occur when the temperature of a reaction is increased?

I. ∆Η of the reaction increases

II. Frequency of the collisions increases

III. Kinetic energy of the reactants increases

A. I and II only.

B. I and III only.

C. II and III only.

D. I, II and III.

4. Which of the following is true for an activated complex?

A. stable and has low PE

B. stable and has high PE

C. unstable and has low PE

D. unstable and has high PE

5. As you increase the temperature of a reaction, the

A. rate increases and the time required for the reaction increases.

B. rate increases and the time required for the reaction decreases.

C. rate decreases and the time required for the reaction increases.

D. rate decreases and the time required for the reaction decreases.

6. Which of the following potential energy curves represents a catalyzed endothermic

reaction in the forward direction?

A. I

B. II

C. III

D. IV

January 2001

1. Which of the following units could be used to express reaction rate?

A. mL/s

B. mL/g

C. g/mL

D. mL/mol

2. Consider the reaction:

Zn (s) + 2HCl (aq) � ZnCl2(aq) + H2(g)

The rate of production of ZnCl2 , can be increased by

A. decreasing the [HCl].

B. increasing the temperature.

C. increasing the volume of H2.

D. decreasing the surface area of Zn .

3. The statement, the minimum energy needed to achieve a successful collision, defines

A. entropy.

B. activation energy.

C. the DH of reaction.

D. the activated complex.

4. As an activated complex changes to products,

A. potential energy changes to kinetic energy.

B. kinetic energy changes to potential energy.

C. kinetic energy changes to activation energy.

D. potential energy changes to activation energy.

5. Consider the following PE diagram for an uncatalysed and a catalyzed reaction:

Which of the following describes the forward catalyzed reaction?

6. A substance that increases the rate of a reaction without appearing in the equation

for the overall reaction is a(n)

A. product.

B. catalyst.

C. reactant.

D. intermediate.

April 2001

1. Which of the following reactions occurs most rapidly at standard conditions?

A. 2Fe (s) + O2(g) � 2FeO(s)

B. CaO(s) + 3C(s) � CaC2(s) + CO(g)

C. SnO2(s) + 2CO(g) � Sn(s) + 2CO2(g)

D. 2AgNO3(aq) + Na2CrO4(aq) � Ag2CrO4(s) + 2NaNO3(aq)


CaO (s) + 2HCl (aq) � CaCl2 (aq) + H2O (l) Which of the following could be used to measure the rate of this reaction?

A. change in acidity

B. change in volume

C. change in pressure

D. change in total mass

3. In order for a collision between reactant particles to be successful

A. ∆H must be positive.

B. the system must be closed.

C. there must be sufficient KE.

D. the change in KE must be less than the change in PE.


The activation energy for the forward reaction is represented by

A. I

B. II

C. III

D. IV

5. What is the relationship between the activation energy and the rate of a reaction?

A. When the activation energy is high, the rate of reaction is fast.

B. When the activation energy is low, the rate of reaction is slow.

C. When the activation energy is high, the rate of reaction is slow.

D. There is no relationship between activation energy and rate of reaction.


Step 1. OCl- + H2O � HOCl + OH

-

Step 2. I- + HOCl � HOI + Cl

-

Step 3. HOI + OH- � H2O + OH

-

Which of the following is correct for the overall reaction?

A. HOI is a product.

B. H2O is a reactant.

C. HOCl is a catalyst.

D. OH- is a reaction intermediate.

June 2001

1. Which of the following reactions is slowest at room temperature?

A. NH3(g) + HCl(g) � NH4Cl (s)

B. MgCl2(s) + Ca(s) � Mg(s) + CaCl2(s)

C. HCl(aq) + NaOH(aq) � NaCl (aq) + H2O(l)

D. Ba(NO3)2 (aq) + Na2SO4(aq) � BaSO4(s) + 2NaNO3(aq)


COCl2(g) � CO(g) + Cl2(g)

Which of the following could be used to determine reaction rate in a closed system?

A. a decrease in gas pressure

B. an increase in gas pressure

C. a decrease in the mass of the system

D. an increase in the mass of the system

3. Activation energy is defined as the

A. ∆H

B. average kinetic energy.

C. energy of a particle’s motion.

D. minimum energy needed for a successful collision.

4. Which of the following reactions is endothermic?

A. CH4(g) + 2O2(g) � CO2(g) + 2H2O(l) + 890.3kJ

B. 2Na2O2 (s) + 2H2O (l) –287.0 kJ � 4NaOH(aq) + O2(g)

C. CaO(s) + H2O(l) � Ca(OH)2 (aq) ∆H= -65.2kJ

D. CaO(s) + 3C(s) � CaC2(s) + CO(g) ∆H= +464.8kJ

5. The following diagram shows reactant molecules approaching one another:

What is happening to the kinetic energy and the potential energy?

6. A proposed mechanism for a reaction is:

Step 1. H3O+ + I

- � HI + H2O

Step 2. H2O2 + HI � H2O + HOI

Step 3. HOI + H3O+ + I

- � 2H2O + I2

Step 4. I2 + I- � I3

-

In the above mechanism, which of the following is true for the overall reaction?

A. HI is a catalyst

B. H3O+ is a product

C. H2O2 is a reactant

D. H2O is an intermediate

August 2001


N2H4(l) + 2H2O2(l) � N2(g) + 4H2O(l)

In 5.0seconds, 0.015mol of H2O2 is consumed. The rate of production of N2 is

A. 1.5 X 10-3

mol/s

B. 3.0 X 10-3

mol/s

C. 6.0 X10-3

mol/s

D. 1.5 X10-2

mol/s


3Fe2O3(s) + CO(g) � 2Fe3O4(s) + CO2(g) + 46kJ

Which of the following would cause the rate of the reaction to increase?

A. removing the Fe3O4

B. decreasing the temperature

C. increasing the surface area of Fe2O3

D. increasing the volume of the reaction vessel

3. Activation energy is described as

A. the energy of the activated complex.

B. a point on the PE diagram where KE = PE.

C. the unstable high PE structural arrangement of atoms.

D. the minimum PE difference between the activated complex and the reactants.

4. What happens to the activation energy and ∆H when a catalyst is added to a reaction?

5. Consider the following potential energy diagram for a reaction:

What is the value of ∆H for this reaction?

A. -120 kJ

B. -30 kJ

C. +30 kJ

D. +120 kJ

6. A substance that is produced in one step in a reaction mechanism and consumed

in a subsequent step, without appearing in the overall reaction, is a(n)

A. catalyst.

B. product.

C. reactant.

D. intermediate.

January 2002

1. Which of the following has the greatest reaction rate?

A. C(s) + O2(g) � CO2(g)

B. 2H2O2 (l) � 2H2O (l) + O2 (g)

C. 2Al (s) + 3CuCl2(aq) � 2AlCl3(aq) + 3Cu(s)

D. NaCl(aq) + AgNO3(aq) � AgCl(s) + NaNO3(aq)

2. Which factor explains why potassium generally reacts faster than sodium?

A. surface area

B. temperature

C. concentration

D. nature of reactants

3. What happens to the PE and KE of the reactants particles as the activated complex is

formed?

PE KE .

A. increases decreases

B. increases increases

C. decreases decreases

D. decreases increases


What are the values of ∆H and activation energy (Ea) for the forward reaction?


Which of the following is a reactant in the overall reaction?

A. Cl

B. HCl

C. CCl3

D. CHCl3

6. Consider the following PE diagram for a catalyzed and uncatalyzed reaction:

Which of the following describes the reverse reaction?

April 2002

1. Which of the following could be used to describe the rate of a reaction?

A. change in time

change in mass

B. change in mass

change in volume

C. change in volume

change in time

D. change in volume

change in mass


2H2O2(aq) � 2H2O(l) + O2(g)

Which factor explains why the above reaction speeds up in the presence of MnO2 (s)?

A. temperature C. nature of reactants

B. concentration D. presence of catalyst

3. What happens to the potential energy and the total energy as an activated complex

changes into products?


Which of the following describes the type of reaction and H for the reverse reaction?

5. Consider the following diagram for a catalyzed and uncatalyzed reaction:

Which of the following describes the forward reaction?


NO2 + SO2 � SO3 + NO

NO + ½ O2� NO2

Identify the catalyst.

A. O2

B. NO

C. SO2

D. NO2

Unit I Multiple Choice Answers Jan 99 April 99 June 99 Aug 99 1 C 1 D 1 D 1 B

2 B 2 D 2 A 2 B

3 D 3 D 3 B 3 C

4 C 4 A 4 C 4 A

5 A 5 C 5 A 5 D

6 C 6 B 6 D 6 B

Jan 00 Apr 00 June 00 Aug 00 1 B 1 B 1 A 1 C

2 C 2 A 2 D 2 B

3 D 3 B 3 C 3 C

4 A 4 D 4 C 4 D

5 B 5 A 5 B 5 B

6 D 6 D 6 B 6 D

Jan 01 Apr 01 June 01 Aug 01 1 A 1 D 1 B 1 A

2 B 2 A 2 B 2 C

3 B 3 C 3 D 3 D

4 A 4 B 4 D 4 C

5 A 5 C 5 B 5 B

6 B 6 D 6 C 6 D

Jan 02 Apr 02 1 D 1 C

2 D 2 D

3 A 3 D

4 A 4 B

5 D 5 A

6 A 6 D

Reaction Kinetics Multiple Choiceabbycloud.ca/andrewpenner/wp-content/uploads/2015/11/ReactKinM… · The rate of consumption of Ca is A. 0.00208 mol/min B. 0.0833 mol/min C. 0.125

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