Question 1

For which of the following reactions is ∆S° a positive value?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) C) and D)
F) A) and D)

Question 2

Which of the following statements is true?

Accepted Answer

A)  Ionic intermediates are formed in radical reactions.
B)  Radicals are intermediates in polar reactions.
C)  Carbocations are electrophiles.
D)  Radicals are nucleophiles.E) C) and D)
F) B) and C)

Question 3

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.E) C) and D)
F) All of the above

Question 4

The conversion of acetyl chloride to methyl acetate occurs via the following two-step mechanism:
-OCH3] B) Rate = k [acetyl chloride] C) Rate = k [-OCH3] D) Rate = k [acetyl chloride] [-OCH3]2" class="answers-bank-image d-inline" rel="preload" >
What is the rate equation for this reaction if the first step is rate determining?

Accepted Answer

A)  Rate = k [acetyl chloride] [-OCH3]
B)  Rate = k [acetyl chloride]
C)  Rate = k [-OCH3]
D)  Rate = k [acetyl chloride] [-OCH3]2E) All of the above
F) None of the above

Question 5

Which reaction is fast and has Keq = 1?
eq = 1?   A) A B) B C) C" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  A
B)  B
C)  CD) A) and B)
E) All of the above

Question 6

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.E) A) and B)
F) C) and D)

Question 7

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/molE) All of the above
F) C) and D)

Question 8

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

Accepted Answer

A)  Keq > 1 when DG° > 0
B)  Keq > 1 when DG° 
C)  Keq 
D)  Keq < 1 when DG° = 0E) C) and D)
F) A) and D)

Question 9

Which of the following statements about enzymes is true?

Accepted Answer

A)  Enzymes increase the activation energy for a reaction.
B)  Enzymes decrease the equilibrium constant.
C)  Enzymes shift the equilibrium to favor the product.
D)  Enzymes lower the transition state for the rate-determining step.E) A) and B)
F) A) and C)

Question 10

Which of the following statements is true?

Accepted Answer

A)  Bond dissociation energies increase down a column of the periodic table.
B)  When DH° is positive, more energy is released in forming bonds than is needed to break bonds.
C)  When DH° is negative, more energy is needed to break bonds than is released in forming bonds.
D)  Bond dissociation energies decrease down a column of the periodic table.E) B) and D)
F) A) and B)

Question 11

The DG° (free energy change)  for the conversion of A to B is predicted to be which of the following?
 0 D) Cannot be determined from the information provided" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  DG° = 0
B)  DG° 
C)  DG° > 0
D)  Cannot be determined from the information providedE) C) and D)
F) All of the above

Question 12

If the conversion of A to B is slow and B to C is fast, what is the rate equation for this reaction?
3) 2CHCl][H2O] B) Rate = k[(CH3) 2CHCl] C) Rate = k[(CH3) 2CH]+[H2O] D) Rate = k[(CH3) 2CH]+" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  Rate = k[(CH3) 2CHCl][H2O]
B)  Rate = k[(CH3) 2CHCl]
C)  Rate = k[(CH3) 2CH]+[H2O]
D)  Rate = k[(CH3) 2CH]+E) None of the above
F) B) and C)

Question 13

The conversion of acetyl chloride to methyl acetate occurs via the following two-step mechanism:

The conversion of acetyl chloride to methyl acetate would be classified as which of the following?

Accepted Answer

A)  Addition
B)  Elimination
C)  Substitution
D)  None of theseE) B) and C)
F) A) and D)

Question 14

Which of the following statements about equilibrium is true?

Accepted Answer

A)  Equilibrium favors the products when the energy of the products is higher than the energy of the reactants.
B)  Equilibrium favors the reactants when the energy of the product is lower than the energy of the reactants.
C)  Equilibrium favors the products when they are less stable than the starting material of a reaction.
D)  Equilibrium favors the products when they are more stable than the starting material of a reaction.E) A) and B)
F) None of the above

Question 15

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.E) A) and C)
F) A) and B)

Question 16

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.E) None of the above
F) B) and D)

Question 17

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

Accepted Answer

A)  A
B)  B
C)  C
D)  DE) A) and C)
F) A) and B)

Question 18

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.E) A) and B)
F) A) and C)

Question 19

The conversion of acetyl chloride to methyl acetate occurs via the following two-step mechanism:
-OCH3 were increased 5 times, what would happen to the rate of the reaction? A) Rate would become one fifth B) Rate would increase 25 times C) Rate would increase 5 times D) Rate would remain unchanged" class="answers-bank-image d-inline" rel="preload" >
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 unchangedE) A) and B)
F) A) and C)

Question 20

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

Accepted Answer

A)  Addition reaction.
B)  Elimination reaction.
C)  Substitution reaction.
D)  Oxidation-reduction reaction.E) B) and D)
F) B) and C)

Exam 6: Understanding Organic Reactions

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?

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For which of the following reactions is ∆S° a positive value?

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Which of the following statements about bond breaking is true?

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

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

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

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Which of the following statements about equilibrium is true?

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Which of the following statements about elimination reactions is true?

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Which of the following statements is not true?

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Which of the following statements is true?

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The conversion of acetyl chloride to methyl acetate occurs via the following two-step mechanism: What is the rate equation for this reaction if the first step is rate determining?

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The conversion of acetyl chloride to methyl acetate occurs via the following two-step mechanism: The conversion of acetyl chloride to methyl acetate would be classified as which of the following?

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

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

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Which reaction is fast and has Keq = 1?

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Which of the following statements about enzymes is true?

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

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Which of the following statements is true?

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

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Which of the following statements is not true?

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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?

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

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Which reaction is fast and has K_eq = 1?

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