Question 1

What type of bond cleavage takes place in/what type of intermediate is produced in the following reaction?

Accepted Answer

A) Homolysis/Radical 
B) Homolysis/Carbocation 
C) Heterolysis/Carbocation 
D) Heterolysis/Carbanion 
A) Homolysis/Radical 
B) Homolysis/Carbocation 
C) Heterolysis/Carbocation 
D) Heterolysis/Carbanion

Question 2

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.

Question 3

The conversion of acetyl chloride to methyl acetate occurs via the following two-step mechanism:   If the concentration of -OCH3 were increased 5 times,what would happen to the rate of the reaction?

Accepted Answer

A) Rate would become one fifth 
B) Rate would increase 25 times 
C) Rate would increase 5 times 
D) Rate would remain unchanged 
A) Rate would become one fifth 
B) Rate would increase 25 times 
C) Rate would increase 5 times 
D) Rate would remain unchanged

Question 4

The symbol Δ stands for ________ in a chemical reaction.

Accepted Answer

A) light 
B) heat 
C) reactant 
D) product 
A) light 
B) heat 
C) reactant 
D) product

Question 5

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 6

Which of the following statements is not true?

Accepted Answer

A) Two reactions can have identical values for DH° but very different Ea values. 
B) The larger the activation energy,the slower the reaction. 
C) DH° determines the height of the energy barrier. 
D) The lower the activation energy,the faster the reaction. 
A) Two reactions can have identical values for DH° but very different Ea values. 
B) The larger the activation energy,the slower the reaction. 
C) DH° determines the height of the energy barrier. 
D) The lower the activation energy,the faster the reaction.

Question 7

Which of the Keq corresponds to the most negative value of DG°?

Accepted Answer

A) Keq = 1 
B) Keq = 101 
C) Keq = 102 
D) Keq = 103 
A) Keq = 1 
B) Keq = 101 
C) Keq = 102 
D) Keq = 103

Question 8

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 9

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 10

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

Accepted Answer

A) DG° = 0 
B) DG°  0 
D) Cannot be determined from the information provided 
A) DG° = 0 
B) DG°  0 
D) Cannot be determined from the information provided

Question 11

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

Accepted Answer

A) DG° 
B) DH° 
C) Keq 
D) Ea 
A) DG° 
B) DH° 
C) Keq 
D) Ea

Question 12

Which of the following statements about elimination reactions is true?

Accepted Answer

A) Two σ bonds are broken. 
B) Two σ bonds are formed. 
C) Two π bonds are broken. 
D) Two π bonds are formed. 
A) Two σ bonds are broken. 
B) Two σ bonds are formed. 
C) Two π bonds are broken. 
D) Two π bonds are formed.

Question 13

Which compound would you predict to be highest in energy?

Accepted Answer

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

Question 14

Using the bond dissociation energies given,calculate DH° for the following reaction.

Accepted Answer

A) +3 KJ/mol 
B) -3 KJ/mol 
C) -67 KJ/mol 
D) +70 KJ/mol 
A) +3 KJ/mol 
B) -3 KJ/mol 
C) -67 KJ/mol 
D) +70 KJ/mol

Question 15

Which of the following statements about addition reactions is true?

Accepted Answer

A) Two π bonds are formed. 
B) Two π bonds are broken. 
C) Two σ bonds are formed. 
D) One π bond is formed. 
A) Two π bonds are formed. 
B) Two π bonds are broken. 
C) Two σ bonds are formed. 
D) One π bond is formed.

Question 16

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 17

Which reaction is fast and has Keq = 1?

Accepted Answer

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

Question 18

Which of the Keq corresponds to the lowest value of DG°?

Accepted Answer

A) Keq = 10-3 
B) Keq = 10-2 
C) Keq = 10-1 
D) DG° cannot be determined. 
A) Keq = 10-3 
B) Keq = 10-2 
C) Keq = 10-1 
D) DG° cannot be determined.

Question 19

Which reaction has a positive DG°,assuming that entropy changes are negligible compared to enthalpy changes?

Accepted Answer

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

Question 20

Which of the following statements about the equilibrium constant,Keq,is true?

Accepted Answer

A) When Keq > 1,the equilibrium favors the reactants. 
B) When Keq eq tells about the position of equilibrium. 
D) For a reaction to be useful,the equilibrium must favor the reactants. 
A) When Keq > 1,the equilibrium favors the reactants. 
B) When Keq eq tells about the position of equilibrium. 
D) For a reaction to be useful,the equilibrium must favor the reactants.

Exam 6: Understanding Organic Reactions

What type of bond cleavage takes place in/what type of intermediate is produced in the following reaction?

Which of the following statements is not true?

The conversion of acetyl chloride to methyl acetate occurs via the following two-step mechanism: If the concentration of -OCH3 were increased 5 times,what would happen to the rate of the reaction?

The symbol Δ stands for ________ in a chemical reaction.

Which of the following statements is not true?

Which of the following statements is not true?

Which of the Keq corresponds to the most negative value of DG°?

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

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

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

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

Which of the following statements about elimination reactions is true?

Which compound would you predict to be highest in energy?

Using the bond dissociation energies given,calculate DH° for the following reaction.

Which of the following statements about addition reactions is true?

Which of the following statements is true?

Which reaction is fast and has Keq = 1?

Which of the Keq corresponds to the lowest value of DG°?

Which reaction has a positive DG°,assuming that entropy changes are negligible compared to enthalpy changes?

Which of the following statements about the equilibrium constant,Keq,is 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 Related Compounds

Alkenes and Addition Reactions

Alkynes and Synthesis

Oxidation and Reduction

Radical Reactions

Conjugation,resonance,and Dienes

Benzene and Aromatic Compounds

Reactions of Aromatic Compounds

Introduction to Carbonyl Chemistry; Organometallic Reagents; Oxidation and Reduction

Aldehydes and Ketones - Nucleophilic Addition

Carboxylic Acids and the Acidity of the O-H Bond

Carboxylic Acids and Their Derivatives Nucleophilic Acyl Substitution

Substitution Reactions of Carbonyl Compounds at the a Carbon

Carbonyl Condensation Reactions

Amines

Carbon-Carbon Bond-Forming Reactions in Organic Synthesis

Pericyclic Reactions

Carbohydrates

Amino Acids and Proteins

Synthetic Polymers

Lipids

Spectroscopy A: Mass Spectrometry

Spectroscopy B: Infrared Spectroscopy

Spectroscopy C: Nuclear Magnetic Resonance Spectroscopy

Filters

The conversion of acetyl chloride to methyl acetate occurs via the following two-step mechanism: If the concentration of ^-OCH₃ were increased 5 times,what would happen to the rate of the reaction?

Which of the K_eq corresponds to the most negative value of DG°?

Which reaction is fast and has K_eq= 1?

Which of the K_eq corresponds to the lowest value of DG°?

Which of the following statements about the equilibrium constant,K_eq,is true?