Question 1

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 
C)  The size of Keq tells about the position of equilibrium.
D)  For a reaction to be useful,the equilibrium must favor the reactants.

Question 2

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

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.

Question 4

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.

Question 5

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

Question 6

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.

Question 7

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.

Question 8

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.

Question 9

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

Question 10

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 unchanged

Question 11

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

Question 12

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.

Question 13

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.

Question 14

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)  C

Question 15

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 provided

Question 16

The symbol Δ stands for ________ in a chemical reaction.

Accepted Answer

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

Question 17

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

Question 18

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

Accepted Answer

A)  A
B)  B
C)  C

Question 19

Which compound would you predict to be highest in energy?

Accepted Answer

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

Question 20

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

Accepted Answer

A)  DG°
B)  DH°
C)  Keq
D)  Ea

Exam 6: Understanding Organic Reactions

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

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The symbol Δ stands for ________ in a chemical reaction.

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Which of the following statements is not true?

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

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Which of the following statements about elimination reactions is true?

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

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

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

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Which compound would you predict to be highest in energy?

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

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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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Which of the following statements about addition 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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Which of the following statements is not true?

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Which reaction is fast and has Keq = 1?

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

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

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

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Which of the following statements about the equilibrium constant,K_eq,is 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 reaction is fast and has K_eq= 1?

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

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

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