Deck 14: Chemical Kinetics

Question 1

The reaction rate of a _____ reaction depends on the surface area of the more condensed phase.

Answer 1

heterogeneous

Question 2

The _____ rate of a reaction is the reaction rate at any given point in time.

Answer 2

instantaneous

Question 3

If there is contact between the constituent particles of two substances, the reaction rate will be zero.

Answer 3

False

Question 4

Reaction rates generally decrease with time as reactant concentrations increase.

Question 5

Which of the following is used to calculate the overall reaction order?

A) $\mathrm { m } / \mathrm { n }$
B) $m \times n$
C) $m + n$
D) $\mathrm { m } ^ { \mathrm { n } }$
E) $\text { m-n }$

Question 6

Which of the following is the unit for reaction rate?

A) kJ/mol
B) C.m
C) kg.m²/s²
D) M/s
E) kJ/g

Question 7

Which of the following best describes chemical kinetics?

A) It is the enthalpy change that occurs when a solid ionic compound is transformed into gaseous ions.
B) It is the process of converting one element to another.
C) It is a methodology that combines chemical reactions and stoichiometric calculations to determine the concentrations of substances present in a sample.
D) It is the study of reaction rates, the changes in the concentrations of reactants and products with time.
E) It is a complete description of the system at a given time, including its temperature and pressure, the amount of matter it contains, its chemical composition, and the physical state of the matter.

Question 8

The _____ refers to the numbers that indicate the degree to which the reaction rate depends on the concentration of each reactant.

Question 9

Explain the effect of temperature on reaction rates with an example.

Question 10

The numerical value of the proportionality constant (k) changes as the reaction progresses under a given set of conditions.

Question 11

The reaction rate of virtually all reactions decreases with increasing temperature.

Question 12

A _____ is a substance that participates in a chemical reaction and increases the reaction rate without undergoing a net chemical change itself.

Question 13

Which of the following is true about the factors that affect reaction rates?

A) The reaction rate usually decreases as the concentration of the reactants increases.
B) The reaction rate of virtually all reactions decreases with increasing temperature.
C) The number of collisions between reactants per unit time is substantially reduced relative to the homogeneous case.
D) Catalysts do not influence the reaction and keep the reaction rate constant.
E) The reaction rates of most reactions increase rapidly with increasing solvent viscosity.

Question 14

The reaction rates of most reactions increase rapidly with increasing solvent viscosity.

Question 15

A _____ rate law expresses the reaction rate in terms of changes in the concentration of one or more reactants over a specific time interval.

Question 16

Calculate the reaction rate of SO₂(g) in the following reaction, using the data provided in the following table. $2 \mathrm{SO}_{2}(\mathrm{~g})+\mathrm{O}_{2}(\mathrm{~g})$$\rightarrow$$2 \mathrm{SO}_{3}(\mathrm{~g})$

$\begin{array}{|l|l|l|l|}\hline \text { Time(s) } &{\left[\mathrm{SO}_{2}\right](\mathrm{M})} & {\left[\mathrm{O}_{2}\right](\mathrm{M})} & {\left[\mathrm{SO}_{3}\right](\mathrm{M})} \\\hline 200 & 0.0235 & 0.0520 & 0.0100 \\\hline 520 & 0.0146 & 0.0410 & 0.0208 \\\hline\end{array}$

A) 5.7 $\times 10 ^ { - 6 } \mathrm { M } / \mathrm { S }$
B) 2.5 $\times 10 ^ { - 6 } \mathrm { M } / \mathrm { S }$
C) 4.3 $\times 10 ^ { - 6 } \mathrm { M } / \mathrm { S }$
D) 1.3 $\times 10 ^ { - 6 } \mathrm { M } / \mathrm { S }$
E) 3.8 $\times 10 ^ { - 6 } \mathrm { M } / \mathrm { S }$

Question 17

Differential rate laws are generally used to describe what is occurring on a molecular level during a reaction.

Question 18

The reaction rate of a heterogeneous reaction depends on the surface area of the more condensed phase.

Question 19

A(n)_____ rate law describes the reaction rate in terms of the initial concentration and the measured concentration of one or more reactants after a given amount of time.

A) homogeneous
B) degenerate
C) differential
D) heterogeneous
E) integrated

Question 20

Distinguish between differential and integrated rate laws.

Question 21

A graph of the concentration of any reactant as a function of time is a straight line with a slope of k.

Question 22

_____ reaction is one in which two smaller molecules, each called a monomer, combine to form a larger molecule.

A) Hydrolysis
B) Hybridization
C) Deformation
D) Fermentation
E) Dimerization

Question 23

Explain the zeroth-order reaction that takes place in the human liver during the oxidation of ethanol.

Question 24

Which of the following is an example of first-order reactions?

A) The hydrolysis of the anticancer drug cisplatin
B) The hydrolysis of aspirin
C) The oxidation of ethanol (from alcoholic beverages) to acetaldehyde in the liver
D) The reaction of t-butyl bromide with water to give t-butanol
E) The decomposition of $\mathrm { N } _ { 2 } \mathrm { O }$ on a platinum surface

Question 25

The following is an example of a first-order reaction involving the _____.

A) reaction of t-butyl bromide with water to give t-butanol
B) hydrolysis of the anticancer drug cisplatin
C) oxidation of ethanol to acetaldehyde in the liver
D) decomposition of N₂O on a platinum surface
E) hydrolysis of aspirin

Question 26

Which of the following is an example of first-order reactions?

A) The decomposition of N₂O to N₂ and O₂
B) The reaction of t-butyl bromide with water to give t-butanol
C) The decomposition of HI to I₂ and H₂
D) A dimerization reaction
E) The oxidation of ethanol (from alcoholic beverages) to acetaldehyde in the liver

Question 27

In second-order reactions, doubling the concentration of the reactant quadruples the reaction rate.

Question 28

For a given number of atoms, isotopes with longer half-lives decay more rapidly.

Question 29

The rate of decay is the decrease in the number of a radioisotope's nuclei per unit time.

Question 30

A _____ order reaction is one whose rate is independent of concentration.

A) first
B) third
C) last
D) second
E) zeroth

Question 31

If a plot of reactant concentration versus time is not linear but a plot of the natural logarithm of reactant concentration versus time is linear, then the reaction is _____ order.

A) third
B) first
C) fourth
D) second
E) zeroth

Question 32

Which of the following is true of zeroth-order reactions?

A) The rate is dependent on the reactant concentration.
B) The differential rate law is rate = k.
C) The graph of the reactant concentration as a function of time is a straight line with slope of k.
D) It can be written in a form such that the exponent of the reactant in the rate law is 1.
E) The graph of the product concentration as a function of time is a straight line with slope of -k.

Question 33

The following graph representing the concentration of the reactant versus time refers to _____-order reaction.

A) first
B) fourth
C) second
D) zeroth
E) third

Question 34

The hydrolysis of the anticancer drug cisplatin is an example of _____ order reaction.

A) first
B) second
C) last
D) third
E) zeroth

Question 35

For two or more reactions of the same order, the reaction with the smallest rate constant is the fastest.

Question 36

The following graph represents the straight-line plot to determine the rate constant of a _____-order reaction.

A) first
B) fourth
C) second
D) zeroth
E) third

Question 37

The sequence of reactions that occur at the molecular level during a reaction is called _____.

Question 38

A linear change in concentration with time is a clear indication of a _____ order reaction.

Question 39

The half-life of a second-order reaction under a given set of reaction conditions is a constant.

Question 40

The rate of radioactive decay is dependent on temperature.

Question 41

A species in a reaction mechanism that does not appear in the balanced chemical equation for the overall reaction is known as the _____.

Question 42

The general rate law for a unimolecular elementary reaction (A → products) is rate = k[A].

Question 43

The _____ of an elementary reaction is the number of molecules that collide during any step in a reaction mechanism.

A) molality
B) polarizability
C) molarity
D) molecularity
E) mass number

Question 44

_____ is a reaction mechanism in which one or more elementary reactions that contain a highly reactive species repeat again and again during the reaction process.

A) Transmutation
B) Reforming
C) Chain reaction
D) Galvanizing
E) Cracking

Question 45

The half-life of a _____ reaction is independent of the concentration of the reactants.

Question 46

Explain chain reactions.

Question 47

In the following reaction, NO₃ molecule does not appear in the balanced chemical equation for the overall reaction. This indicates that NO₃ is a(n) _____ in the reaction. $$\begin{array} { c } \mathrm { NO } _ { 2 } + \mathrm { NO } _ { 2 } \longrightarrow \mathrm { NO } _ { 3 } + \mathrm { NO } \\\mathrm { NO } _ { 3 } + \mathrm { CO } \rightarrow \mathrm { NO } _ { 2 } + \mathrm { CO } _ { 2 } \\\hline\mathrm { NO } _ { 2 } + \mathrm { CO } \rightarrow \mathrm { NO } + \mathrm { CO } _ { 2 }\end{array}$$

A) intermediate
B) micelle
C) adduct
D) polymer
E) emulsion

Question 48

The rate law for a termolecular elementary reaction of the form $2 A + B \rightarrow \text { product }$ is _____.

A) $k [ \mathrm {~A} ] [ \mathrm { B } ]$
B) $k [ \mathrm {~A} ] ^ { 2 } [ \mathrm {~B} ]$
C) $k [ \mathrm {~A} ]$
D) $k [ \mathrm {~A} ] ^ { 2 }$
E) $k [ \mathrm {~A} ] [ \mathrm { B } ] [ \mathrm { C } ]$

Question 49

The reaction rate will vary with concentration.

Question 50

The _____ of a reaction is the time required for the reactant concentration to decrease to one-half its initial value.

A) wavelength
B) frequency
C) overtone
D) amplitude
E) half-life

Question 51

_____ reaction involves each of the complex series of reactions that take place in a stepwise fashion to convert reactants to products.

Question 52

A compound hydrolyzes in water with a rate constant of $1.9 \times 10 ^ { - 3 } \mathrm {~min} ^ { - 1 }$ at pH 6.0 and $26 ^? \mathrm { C }$ . If a freshly prepared solution of the compound has a concentration of 0.086M, what is the percent completion of the reaction after 3 half-lives?

A) 63%
B) 87%
C) 94%
D) 79%
E) 56%

Question 53

A compound hydrolyzes in water with a rate constant of $1.9 \times 10 ^ { - 3 } \mathrm {~min} ^ { - 1 }$ at pH 6.0 and $26^? \mathrm { C }$ . If a freshly prepared solution of the compound has a concentration of 0.086 M, the concentration of the compound after 3 half-lives is _____ M.

A) 0.0120
B) 0.0110
C) 0.0106
D) 0.0108
E) 0.0104

Question 54

_____ is the emission of a particle or a photon that results from the spontaneous decomposition of the unstable nucleus of an atom.

A) Photoelectric effect
B) Electron shielding
C) Blackbody radiation
D) Greenhouse effect
E) Radioactivity

Question 55

Explain the radioisotope dating techniques.

Question 56

Radicals are species that have one or more unpaired valence electrons.

Question 57

The _____ of a sample of a radioactive substance is the decrease in the number of radioactive nuclei per unit time.

Question 58

A compound hydrolyzes in water with a rate constant of $1.9 \times 10 ^ { - 3 } \mathrm {~min} ^ { - 1 }$ at pH 6.0 and $26 ^{?}\mathrm { C }$ . The half-life for this reaction is _____ min.

A) $3.6 \times 10 ^ { 2 }$
B) $5.1 \times 10 ^ { 2 }$
C) $4.8 \times 10 ^ { 2 }$
D) $6.5 \times 10 ^ { 2 }$
E) $2.9 \times 10 ^ { 2 }$

Question 59

The fastest step in a reaction is the rate-determining step.

Question 60

The rate law for a reaction can be obtained from the overall balanced chemical equation alone.

Question 61

Which heterogeneous catalyst is used in steam reforming?

A) Ni
B) Fe
C) Cu
D) Pd
E) Rh

Question 62

_____ is a constant in the Arrhenius equation which converts concentrations to collisions per second.

Question 63

What does $R$ indicate in the Arrhenius equation?

A) Ideal gas constant
B) Avogadro's number
C) Boltzmann's constant
D) Atomic mass unit
E) Faraday's constant

Question 64

For two similar reactions under comparable conditions, the reaction with the greatest $E _ { a }$ will occur more rapidly.

Question 65

Enzymes are catalysts that occur naturally in living organisms.

Question 66

The fraction of orientations that result in a reaction is called the _____.

Question 67

A catalyst affects $\Delta E$ but not E_a.

Question 68

Which of the following refers to Arrhenius equation?

A) $E = k \frac { Q_1 Q } { r }$
B) $k = A e ^ { - E _ { \mathrm { ? } } / R T }$
C) $\mu = Q r$
D) $V = \frac { n R T } { P }$
E) $c = \lambda v$

Question 69

Which of the following is a commercially important reaction that employs heterogeneous catalysts?

A) Hydroperoxide process
B) Adiponitrile process
C) Olefin polymerization
D) Methanol synthesis
E) Hydroformylation

Question 70

_____ is a substance that participates in a reaction and causes it to occur more rapidly but that can be recovered unchanged at the end of the reaction and reused.

A) Poison
B) Catalyst
C) Polymer
D) Adduct
E) Allotrope

Question 71

Which of the following feature is true about catalysts?

A) Catalysts appear in the overall stoichiometry of the reaction being catalyzed.
B) The reaction rate of a catalyzed reaction is slower than the reaction rate of the uncatalyzed reaction at the same temperature.
C) Catalysts increase the reaction rate of a chemical reaction by being consumed in the process.
D) The net change in energy that results from a reaction is affected by the presence of a catalyst.
E) Catalysts increase the reaction rates of both the forward and the reverse reactions by the same amount.

Question 72

Explain activation energy with an example.

Question 73

Which of the following is a commercially important reaction that employs homogeneous catalysts?

A) Ostwald process
B) Hydroformylation
C) Haber process
D) Methanol synthesis
E) Catalytic hydrogenation

Question 74

The arrangement of atoms that first forms when molecules are able to overcome the activation energy and react is called _____.

A) an activated complex
B) the smectic phase
C) a bilayer
D) the cholesteric phase
E) a micelle

Question 75

According to the _____, a chemical reaction can occur only when the reactant molecules, atoms, or ions collide with more than a certain amount of kinetic energy and in the proper orientation.

A) Lewis bonding model
B) Bohr's model
C) Valence-shell electron-pair repulsion model
D) collision model
E) Rutherford's model

Question 76

Differentiate between heterogeneous and homogeneous catalysts.

Question 77

The activated complex is a reaction intermediate.

Question 78

_____ are enzymes that are able to cleave the amide bonds that hold amino acids together in proteins.

A) Poisons
B) Substrates
C) Adducts
D) Micelles
E) Proteases

Question 79

A steric factor value of 0 indicates that all orientations result in reaction.

Question 80

High-density polyethylene and polypropylene are produced by heterogeneous catalysis