Question 1

Which of the following statements about bond breaking is true?

Accepted Answer

A)  Homolysis and heterolysis require energy. 
B)  In homolysis, the electrons in the bond are divided unequally. 
C)  In heterolysis, the electrons in the bond are divided equally. 
D)  Homolysis generates charged intermediates. 
A)  Homolysis and heterolysis require energy. 
B)  In homolysis, the electrons in the bond are divided unequally. 
C)  In heterolysis, the electrons in the bond are divided equally. 
D)  Homolysis generates charged intermediates. A

Question 2

Which of the following letters represents F1F1F1S1F1F1F10H° for the forward reaction in the following energy diagram?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
A)  A 
B)  B 
C)  C 
D)  D D

Question 3

Which of the following statements is not true?

Accepted Answer

A)  Bond breaking is endothermic. 
B)  The bond dissociation energy for bond breaking is always negative. 
C)  Bond making is exothermic. 
D)  The bond dissociation energy for bond formation is always negative. 
A)  Bond breaking is endothermic. 
B)  The bond dissociation energy for bond breaking is always negative. 
C)  Bond making is exothermic. 
D)  The bond dissociation energy for bond formation is always negative. B

Question 4

Which of the following statements is not true?

Accepted Answer

A)  In polar reactions, a nucleophile reacts with an electrophile. 
B)  Carbocations are electrophiles. 
C)  Carbanions are nucleophiles. 
D)  A half-headed curved arrow shows the movement of an electron pair. 
A)  In polar reactions, a nucleophile reacts with an electrophile. 
B)  Carbocations are electrophiles. 
C)  Carbanions are nucleophiles. 
D)  A half-headed curved arrow shows the movement of an electron pair.

Question 5

The F1F1F1S1F1F1F10G° (free energy change) for the conversion of A to B is predicted to be which of the following?

Accepted Answer

A)  "F1F1F1S1F1F1F10G° = 0" 
B)  "F1F1F1S1F1F1F10G°  0" 
D)  "Cannot be determined from the information provided" 
A)  "F1F1F1S1F1F1F10G° = 0" 
B)  "F1F1F1S1F1F1F10G°  0" 
D)  "Cannot be determined from the information provided"

Question 6

Which of the following expressions summarizes the correct relationship between the free energy change, F1F1F1S1F1F1F10G°, and the equilibrium constant, Keq?

Accepted Answer

A) Keq > 1 when F1F1F1S1F1F1F10G° > 0 B) Keq > 1 when F1F1F1S1F1F1F10G° eq eq < 1 when F1F1F1S1F1F1F10G° = 0 A) Keq > 1 when F1F1F1S1F1F1F10G° > 0 B) Keq > 1 when F1F1F1S1F1F1F10G° eq eq < 1 when F1F1F1S1F1F1F10G° = 0

Question 7

Which of the following reaction quantities will have an effect on reaction rate?

Accepted Answer

A)  "F1F1F1S1F1F1F10G°" 
B)  "F1F1F1S1F1F1F10H°" 
C)  "Keq" 
D)  "Ea" 
A)  "F1F1F1S1F1F1F10G°" 
B)  "F1F1F1S1F1F1F10H°" 
C)  "Keq" 
D)  "Ea"

Question 8

A decrease in which of the following results in an increase in the rate of a chemical reaction?

Accepted Answer

A)  Energy of activation 
B)  Concentration 
C)  Temperature 
D)  Kinetic energy 
A)  Energy of activation 
B)  Concentration 
C)  Temperature 
D)  Kinetic energy

Question 9

Which of the following statements is true?

Accepted Answer

A)  Fast reactions have small rate constants. 
B)  Slow reactions have large rate constants. 
C)  A rate equation contains concentration terms for all reactants involved in a one-step mechanism. 
D)  A rate equation contains concentration terms for all the reactants involved in a multi-step reaction. 
A)  Fast reactions have small rate constants. 
B)  Slow reactions have large rate constants. 
C)  A rate equation contains concentration terms for all reactants involved in a one-step mechanism. 
D)  A rate equation contains concentration terms for all the reactants involved in a multi-step reaction.

Question 10

What kind of reaction does the conversion of A to B represent?

Accepted Answer

A)  Acid-base reaction. 
B)  Elimination reaction. 
C)  Substitution reaction. 
D)  Addition reaction. 
A)  Acid-base reaction. 
B)  Elimination reaction. 
C)  Substitution reaction. 
D)  Addition reaction.

Question 11

Which reaction is fast and has Keq= 1?

Accepted Answer

A)  A 
B)  B 
C)  C 
A)  A 
B)  B 
C)  C

Question 12

What is the name given to the reaction species that lies at an energy minimum between steps on a reaction energy diagram?

Accepted Answer

A)  Transition state 
B)  Activation energy 
C)  Reactive intermediate 
D)  Equilibrium product 
A)  Transition state 
B)  Activation energy 
C)  Reactive intermediate 
D)  Equilibrium product

Question 13

If the conversion of A to B is slow and B to C is fast, what is the rate equation for this reaction?

Accepted Answer

A)  Rate = k[(CH3)2CHCl][H2O] 
B)  Rate = k[(CH3)2CHCl] 
C)  Rate = k[(CH3)2CH]+[H2O] 
D)  Rate = k[(CH3)2CH]+ 
A)  Rate = k[(CH3)2CHCl][H2O] 
B)  Rate = k[(CH3)2CHCl] 
C)  Rate = k[(CH3)2CH]+[H2O] 
D)  Rate = k[(CH3)2CH]+

Question 14

Which of the Keq corresponds to the highest value of F1F1F1S1F1F1F10G°?

Accepted Answer

A)  Keq = 10-1 
B)  Keq = 10-2 
C)  Keq = 10-3 
D)  Keq = 10-5 
A)  Keq = 10-1 
B)  Keq = 10-2 
C)  Keq = 10-3 
D)  Keq = 10-5

Question 15

How many transition states and intermediates would the reaction profile have for the reaction shown below?

Accepted Answer

A)  Three transition states and three intermediates 
B)  Two transition states and two intermediates 
C)  Three transition states and two intermediates 
D)  Two transition states and three intermediates 
A)  Three transition states and three intermediates 
B)  Two transition states and two intermediates 
C)  Three transition states and two intermediates 
D)  Two transition states and three intermediates

Question 16

Which of the following statements about elimination reactions is true?

Accepted Answer

A)  Two F1F1F1S1F1F1F10 bonds are broken. 
B)  Two F1F1F1S1F1F1F10 bonds are formed. 
C)  Two F1F1F1S1F1F1F10 bonds are broken. 
D)  Two F1F1F1S1F1F1F10 bonds are formed. 
A)  Two F1F1F1S1F1F1F10 bonds are broken. 
B)  Two F1F1F1S1F1F1F10 bonds are formed. 
C)  Two F1F1F1S1F1F1F10 bonds are broken. 
D)  Two F1F1F1S1F1F1F10 bonds are formed.

Question 17

How many transition states are present in the reaction in the energy diagram?

Accepted Answer

A)  0 
B)  1 
C)  2 
D)  3 
A)  0 
B)  1 
C)  2 
D)  3

Question 18

Which of the Keq corresponds to the lowest value of F1F1F1S1F1F1F10G°?

Accepted Answer

A)  "Keq = 10-3" 
B)  "Keq = 10-2" 
C)  "Keq = 10-1" 
D)  "F1F1F1S1F1F1F10G° cannot be determined" 
A)  "Keq = 10-3" 
B)  "Keq = 10-2" 
C)  "Keq = 10-1" 
D)  "F1F1F1S1F1F1F10G° cannot be determined"

Question 19

Which of the following statements about bond breaking is not true?

Accepted Answer

A)  Homolysis generates uncharged reactive intermediates with unpaired electrons. 
B)  Homolysis require energy but heterolysis does not require energy. 
C)  Heterolysis generates charged intermediates. 
D)  Heterolysis involves unequal sharing of bonding electrons by atoms. 
A)  Homolysis generates uncharged reactive intermediates with unpaired electrons. 
B)  Homolysis require energy but heterolysis does not require energy. 
C)  Heterolysis generates charged intermediates. 
D)  Heterolysis involves unequal sharing of bonding electrons by atoms.

Question 20

Using the bond dissociation energies given, calculate F1F1F1S1?F1F1F10H° for the following reaction. $$\mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } - \mathrm { Br } + \mathrm { H } _ { 2 } \mathrm { O } \longrightarrow \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } - \mathrm { OH } + + \mathrm { HBr }$$ Bond A-B F1F1F1S1?F1F1F10H° KJ/mol
CH3CH2-Br
285
H-OH
498
CH3CH2-OH
393
H-Br
368

Accepted Answer

A)  +108 KJ/mol 
B)  -130 KJ/mol 
C)  -22 KJ/mol 
D)  +22 KJ/mol 
A)  +108 KJ/mol 
B)  -130 KJ/mol 
C)  -22 KJ/mol 
D)  +22 KJ/mol

Exam 6: Understanding Organic Reactions

Which of the following statements about bond breaking is true?

Which of the following letters represents H° for the forward reaction in the following energy diagram?

Which of the following statements is not true?

Which of the following statements is not true?

The G° (free energy change) for the conversion of A to B is predicted to be which of the following?

Which of the following expressions summarizes the correct relationship between the free energy change, G°, and the equilibrium constant, Keq?

Which of the following reaction quantities will have an effect on reaction rate?

A decrease in which of the following results in an increase in the rate of a chemical reaction?

Which of the following statements is true?

What kind of reaction does the conversion of A to B represent?

Which reaction is fast and has Keq= 1?

What is the name given to the reaction species that lies at an energy minimum between steps on a reaction energy diagram?

If the conversion of A to B is slow and B to C is fast, what is the rate equation for this reaction?

Which of the Keq corresponds to the highest value of G°?

How many transition states and intermediates would the reaction profile have for the reaction shown below?

Which of the following statements about elimination reactions is true?

How many transition states are present in the reaction in the energy diagram?

Which of the Keq corresponds to the lowest value of G°?

Which of the following statements about bond breaking is not true?

Structure and Bonding

Acids and Bases

Introduction to Organic Molecules and Functional Groups

Alkanes

Stereochemistry

Alkyl Halides and Nucleophilic Substitution

Alkyl Halides and Elimination Reactions

Alcohols, Ethers and Epoxides

Alkenes

Alkynes

Oxidation and Reduction

Mass Spectrometry and Infrared Spectroscopy

Nuclear Magnetic Resonance Spectroscopy

Radical Reactions

Conjugation, Resonance, and Dienes

Benzene and Aromatic Compounds

Electrophilic Aromatic Substitution

Carboxylic Acids and the Acidity of the O-H Bond

Introduction to Carbonyl Chemistry; Organometallic Reagents; Oxidation and Reduction

Aldehydes and Ketones Nucleophilic Addition

Carboxylic Acids and Derivatives

Substitution Reactions of Carbonyl Compounds at the Alpha-Carbon

Carbonyl Condensation Reactions

Amines

Carbon-Carbon Bond Forming Reactions in Organic Synthesis

Pericyclic Reactions

Carbohydrates

Amino Acids and Proteins

Lipids

Synthetic Polymers

Filters

Which of the following expressions summarizes the correct relationship between the free energy change, G°, and the equilibrium constant, K_eq?

Which reaction is fast and has K_eq= 1?

Which of the K_eq corresponds to the highest value of G°?

Which of the K_eq corresponds to the lowest value of G°?