Deck 6: Chemical Reactivity and Mechanisms

Question 1

Which of the following is the enthalpy of the following reaction?

A)-8 kJ/mol
B)8 kJ/mol
C)-506 kJ/mol
D)63 kJ/mol

Answer 1

-8 kJ/mol

Question 2

Calculate the enthalpy of the following reaction.

Answer 2

29 kJ/mol

Question 3

Does a reaction with a positive $\Delta$ S and a negative $\Delta$ H favor reactants or products?

Answer 3

Products

Question 4

Calculate the enthalpy of the following reaction.

Question 5

Calculate the enthalpy of the following reaction.

Question 6

Which of the following is the enthalpy of the following reaction?

A)-8 kJ/mol
B)8 kJ/mol
C)222 kJ/mol
D)79 kJ/mol

Question 7

What type of cleavage does the following reaction involve?

Question 8

Predict the sign of $\Delta$ G for an endothermic reaction with an increase in entropy.

A)positive
B)negative
C)no change
D)cannot predict

Question 9

Predict the sign of $\Delta$ S of the following reaction?

Question 10

What type of cleavage does the following reaction involve?

A)homolytic
B)heterolytic

Question 11

Does a reaction with a negative $\Delta$ G favor reactants or products?

Question 12

Predict the sign of $\Delta$ S of the following reaction?

A)positive
B)negative
C)no change

Question 13

Predict the sign of $\Delta$ G for an endothermic reaction with a decrease in entropy.

A)positive
B)negative
C)no change
D)cannot predict

Question 14

Does a reaction with a positive $\Delta$ G favor reactants or products?

Question 15

Predict the sign of $\Delta$ S of the following reaction?

A)positive
B)negative
C)no change

Question 16

Predict the sign of $\Delta$ G for an exothermic reaction with a decrease in entropy.

A)positive
B)negative
C)no change
D)cannot predict

Question 17

Does a reaction with a positive $\Delta$ S and a positive $\Delta$ H favor reactants or products?

Question 18

Predict the sign of $\Delta$ G for an exothermic reaction with an increase in entropy.

A)positive
B)negative
C)no change
D)cannot predict

Question 19

Predict the sign of $\Delta$ S of the following reaction?

A)positive
B)negative
C)no change

Question 20

Why is entropy negative for ring closures?

A)Closing a ring results in fewer molecules.
B)Closing a ring results in more molecules.
C)Closing a ring releases energy.
D)Closing a ring restricts the rotation around individual carbon-carbon bonds.

Question 21

Given the following rate law,the reaction is what order in tert-butyliodide?

Question 22

Identify the nucleophilic atom in the following molecule.

Question 23

Identify the nucleophilic atom in the following molecule.

Question 24

Based on the following energy diagram,is the following reaction exothermic or endothermic?

Question 25

Does a reaction with a $\Delta$ H of 14 kJ/mol and a $\Delta$ S of 150 J/molK at 298 K favor reactants or products?

Question 26

What is the energy of activation for the following reaction?

Question 27

Draw an energy diagram for an endothermic reaction with two steps.

Question 28

What is the effect of a catalyst on a reaction?

A)It speeds up the rate.
B)It decreases the entropy.
C)It changes the equilibrium.
D)It makes the products more stable.

Question 29

Given the following rate law,the reaction is what order in sodium cyanide?

Question 30

Given the following rate law,the reaction is what order in MeI?

Question 31

Identify the nucleophilic atom(s)in the following molecule.

Question 32

What is the energy of activation for the following reaction?

Question 33

Which of the following describes the effect of a catalyst on a reaction?

A)It lowers the free energy of the products.
B)It makes the reactants less stable.
C)It changes the equilibrium constant.
D)It lowers the energy of activation.

Question 34

Draw an energy diagram for a three step reaction.

Question 35

Based on the following energy diagram,is the following reaction exothermic or endothermic?

Question 36

Does a reaction with a K_eq = 10 favor reactants or products?

Question 37

Draw an energy diagram for an exothermic concerted reaction.

Question 38

What is a transition state?

A)An isolable intermediate in a reaction.
B)The starting materials of the reaction.
C)A local maximum on the energy diagram.
D)A point between the starting materials and the product.

Question 39

Does a reaction with a $\Delta$ H or 20 kJ/mol and a $\Delta$ S of 10 J/mol K at 298 K favor reactants of products?

Question 40

What is an intermediate?

A)A local maximum on the energy diagram.
B)A point on the reaction pathway that has a discrete lifetime.
C)A point half-way between the starting materials and products.
D)The highest energy compound on an energy diagram.

Question 41

Draw the structure for hydride.

Question 42

For the following reaction step,indicate which pattern it belongs to.

A)Proton Transfer
B)Loss of Leaving Group
C)Nucleophilic Attack
D)Rearrangement

Question 43

For the following reaction step,indicate which pattern it belongs to.

A)Proton Transfer
B)Loss of Leaving Group
C)Nucleophilic Attack
D)Rearrangement

Question 44

For the following reaction step,indicate which pattern it belongs to.

Question 45

Which of the following is hydride?

A)H⁺
B)H
C)H^-
D)H₂

Question 46

For the following reaction step,indicate which pattern it belongs to.

A)Proton Transfer
B)Loss of Leaving Group
C)Nucleophilic Attack
D)Rearrangement

Question 47

Identify the electrophilic site in the following molecule.

A)C
B)O
C)B
D)No electrophilic site

Question 48

Identify the electrophilic atom in the following molecule.

Question 49

For the following reaction step,indicate which pattern it belongs to.

A)Proton Transfer
B)Loss of Leaving Group
C)Nucleophilic Attack
D)Rearrangement

Question 50

Identify the nucleophilic atom in the following molecule.

A)P
B)C
C)H
D)Me

Question 51

What is wrong with the following mechanism?

A)There is no leaving group,so there should be no arrows.
B)The arrow should be removing a proton from the H₂O group.
C)An arrow is also needed to indicate the loss of the leaving group.
D)The arrow indicating the formation of the C-Br bond (nucleophilic attack)should start at the bromide anion.

Question 52

Identify the electrophilic site in the following molecule.

Question 53

Identify the nucleophilic centers in the following molecule.

Question 54

Identify the electrophilic site in the following molecule.

Question 55

For the following reaction step,indicate which pattern it belongs to.

A)Proton Transfer
B)Loss of Leaving Group
C)Nucleophilic Attack
D)Rearrangement

Question 56

For the following reaction step,indicate which pattern it belongs to.

A)Proton Transfer
B)Loss of Leaving Group
C)Nucleophilic Attack
D)Rearrangement

Question 57

What is wrong with the following mechanism?

A)There is no leaving group,so there should be no arrows.
B)The arrow should be removing a proton from the H₂O group.
C)An arrow is also needed to indicate the loss of the leaving group.
D)The arrow is backwards.

Question 58

Identify the nucleophilic centers in the following molecule.

Question 59

Identify the electrophilic atom in the following molecule.

A)C
B)H
C)O of carbonyl
D)C of carbonyl

Question 60

Identify the electrophilic site in the following molecule.

Question 61

What pattern is the second step of this reaction?

Question 62

Identify the sequence of steps in the following reaction.

A)Proton transfer,Proton transfer,Nucleophilic Attack
B)Proton transfer,Loss of leaving group
C)Nucleophilic attack,Proton transfer,Loss of leaving group
D)Proton transfer,Nucleophilic attack,Proton transfer

Question 63

Will the following cation undergo rearrangement?

Question 64

Which of the following is the nucleophilic site in the following reaction?

A)C of the carbonyl
B)O
C)Li
D)Me of Li-Me

Question 65

Identify the sequence of steps in the following reaction.

A)Proton transfer,Proton transfer,Nucleophilic Attack
B)Proton transfer,Loss of leaving group,Nucleophilic attack,Proton transfer
C)Nucleophilic attack,Proton transfer,Loss of leaving group
D)Proton transfer,Loss of leaving group,Proton transfer,Nucleophilic attack

Question 66

Identify the nucleophilic and electrophilic sites in the following reaction.

Question 67

What pattern is the second step of this reaction?

A)Proton Transfer
B)Loss of Leaving Group
C)Nucleophilic Attack
D)Rearrangement

Question 68

Draw arrows for the following reaction.

Question 69

Which of the following is the electrophilic site in the following reaction?

A)C of the carbonyl
B)O
C)Li
D)Me

Question 70

Identify the nucleophilic and electrophilic sites in the following reaction.

Question 71

What pattern is the fourth step of this reaction?

A)Proton Transfer
B)Loss of Leaving Group
C)Nucleophilic Attack
D)Rearrangement

Question 72

What pattern is the second step of this reaction?

A)Proton Transfer
B)Loss of Leaving Group
C)Nucleophilic Attack
D)Rearrangement

Question 73

Will the following cation undergo rearrangement?

Question 74

Identify the sequence of steps in the following reaction.

A)Proton transfer,Proton transfer
B)Proton transfer,Loss of leaving group
C)Nucleophilic attack,Proton transfer
D)Proton transfer,Nucleophilic attack

Question 75

What pattern is the second step of this reaction?

A)Proton Transfer
B)Loss of Leaving Group
C)Nucleophilic Attack
D)Rearrangement

Question 76

Which of the following is the electrophilic site in the following reaction?

A)C of carbonyl
B)O of carbonyl
C)Cl
D)O of alcohol

Question 77

Draw arrows for each step of the following reaction.

Question 78

Identify the sequence of steps in the following reaction.

A)Proton transfer,Proton transfer
B)Proton transfer,Loss of leaving group
C)Nucleophilic attack,Proton transfer
D)Proton transfer,Nucleophilic attack

Question 79

What pattern is the second step of this reaction?

A)Proton Transfer
B)Loss of Leaving Group
C)Nucleophilic Attack
D)Rearrangement

Question 80

Draw arrows for each step of the following reaction.