Question 1

Provide the structure of the carbene that results when diazomethane (shown below) decomposes.

Accepted Answer

The answer of Provide the structure of the carbene that...

Question 2

Consider the reaction (CH3)3CBr + CH3CH2OH →   Experimentally one finds that if the concentration of (CH3)3CBr is tripled, the rate of the reaction triples. One also finds that if the concentration of CH3CH2OH is doubled, the rate of the reaction is unchanged. Which of the following correctly describes the kinetics of this reaction?

Accepted Answer

A)  The reaction is third order in (CH3)3CBr. 
B)  The reaction is first order in CH3CH2OH. 
C)  The reaction is second order overall. 
D)  The reaction is first order overall. 
E)  none of the above 
A)  The reaction is third order in (CH3)3CBr. 
B)  The reaction is first order in CH3CH2OH. 
C)  The reaction is second order overall. 
D)  The reaction is first order overall. 
E)  none of the above D

Question 3

In the reaction of Cl2 with ethane and UV light, which of the following reactions would be a propagation event(s)?
I. Cl∙ + CH3-CH3 → CH3-CH2-Cl + H∙
II. Cl∙ + CH3-CH3 → CH3-H2C∙ + HCl
III. Cl∙ + CH3-H2C∙ → CH3-CH2-Cl
IV. Cl2 + CH3-H2C∙ → CH3-CH2-Cl + Cl∙
V. Cl2 + UV light → C l∙ + Cl∙

Accepted Answer

A)  reactions I and V 
B)  reactions II, III and IV 
C)  reactions I and IV 
D)  reactions II and IV 
E)  reactions I, II and IV 
A)  reactions I and V 
B)  reactions II, III and IV 
C)  reactions I and IV 
D)  reactions II and IV 
E)  reactions I, II and IV D

Question 4

Do you expect the initiation step in the free radical chlorination of 2,2-dimethylpropane to have a positive or negative ΔS? Explain briefly.

Accepted Answer

One expects a positive ΔS for

Question 5

What is meant by the mechanism of a chemical reaction?

Accepted Answer

The mechanism of a reaction is the compl

Question 6

The Arrhenius equation mathematically models which of the following statements?

Accepted Answer

A)  The rate of a chemical reaction increases exponentially with increasing concentration of reactants. 
B)  The rate of a chemical reaction is directly related to the Ea and that increasing the temperature will alter the Ea for that reaction. 
C)  Increasing the temperature of a chemical reaction increases the number of particles in the reaction that have the minimum energy required to meet the Ea. 
D)  The rate of a chemical reaction is exponentially related to the Ea and relatively small differences in the Ea can dramatically affect the reaction rates of similar reactions at the same temperature. 
E)  both C and D 
A)  The rate of a chemical reaction increases exponentially with increasing concentration of reactants. 
B)  The rate of a chemical reaction is directly related to the Ea and that increasing the temperature will alter the Ea for that reaction. 
C)  Increasing the temperature of a chemical reaction increases the number of particles in the reaction that have the minimum energy required to meet the Ea. 
D)  The rate of a chemical reaction is exponentially related to the Ea and relatively small differences in the Ea can dramatically affect the reaction rates of similar reactions at the same temperature. 
E)  both C and D

Question 7

Butylated hydroxytoluene, or BHT, is a potent radical scavenger that is used as a food preservative. It reacts preferentially with free radicals in food to form a new, less reactive resonance stabilized species. The reaction of BHT with a damaging free radical is shown below. Draw two additional resonance structures for the radical form of BHT where the free electron is delocalized.

Accepted Answer

The answer of Butylated hydroxytoluene, or BHT, is a potent...

Question 8

How many distinct monochlorinated products can result when cyclopentane is subjected to free radical chlorination?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 9

When two carbenes collide, they immediately dimerize to give ________.

Accepted Answer

A)  an alkane 
B)  an alkene 
C)  an alkyne 
D)  an aromatic ring 
E)  a carbanion 
A)  an alkane 
B)  an alkene 
C)  an alkyne 
D)  an aromatic ring 
E)  a carbanion

Question 10

The rate of a reaction typically increases as the temperature increases because ________.

Accepted Answer

A)  the A term in the Arrhenius equation increases 
B)  the fraction of molecules with kinetic energy greater than Ea increases 
C)  the activation energy decreases 
D)  the activation energy increases 
E)  the molecules make more collisions with the wall of the reaction vessel 
A)  the A term in the Arrhenius equation increases 
B)  the fraction of molecules with kinetic energy greater than Ea increases 
C)  the activation energy decreases 
D)  the activation energy increases 
E)  the molecules make more collisions with the wall of the reaction vessel

Question 11

The bond dissociation energy is the amount of energy required to break a bond ________.

Accepted Answer

A)  homolytically 
B)  heterolytically 
C)  so as to produce the more stable pair of ions 
D)  via hydrogenation 
E)  none of the above 
A)  homolytically 
B)  heterolytically 
C)  so as to produce the more stable pair of ions 
D)  via hydrogenation 
E)  none of the above

Question 12

In the first propagation step of the free radical chlorination of methane, which of the following occurs?

Accepted Answer

A)  Cl2 dissociates. 
B)  A chlorine radical abstracts a hydrogen. 
C)  A carbon radical reacts with Cl2. 
D)  A carbon radical reacts with a chlorine radical. 
E)  Two chlorine radicals combine. 
A)  Cl2 dissociates. 
B)  A chlorine radical abstracts a hydrogen. 
C)  A carbon radical reacts with Cl2. 
D)  A carbon radical reacts with a chlorine radical. 
E)  Two chlorine radicals combine.

Question 13

Given a K of 0.45 at 25°C, calculate the corresponding ΔG° in kJ/mol. [R = 8.314 J/K∙ mol]

Accepted Answer

Question 14

Write an equation to describe the initiation step in the chlorination of methane.

Accepted Answer

Cl-Cl + ph

Question 15

Provide the major organic product(s) in the reaction below.

Accepted Answer

The answer of Provide the major organic product(s) in the...

Question 16

What is the hybridization of the negatively charged carbon in (CH3)3C:-?

Accepted Answer

Question 17

Given a K of 2.2 at 25°C, calculate the corresponding ΔG° in kJ/mol. [R = 8.314 J/K∙ mol]

Accepted Answer

Question 18

Predict the signs of ΔH° and ΔS° in the reaction of cyclohexene with H2 to form cyclohexane, shown below.

Accepted Answer

Question 19

What is the CCC bond angle in (CH3)3C:-?

Accepted Answer

slightly l

Question 20

Given a reaction in which reactant A is converted only to product B at 25°C, what Keq results if at equilibrium 80% of A has become B?

Accepted Answer

Exam 4: The Study of Chemical Reactions

Provide the structure of the carbene that results when diazomethane (shown below) decomposes.

Do you expect the initiation step in the free radical chlorination of 2,2-dimethylpropane to have a positive or negative ΔS? Explain briefly.

What is meant by the mechanism of a chemical reaction?

The Arrhenius equation mathematically models which of the following statements?

How many distinct monochlorinated products can result when cyclopentane is subjected to free radical chlorination?

When two carbenes collide, they immediately dimerize to give ________.

The rate of a reaction typically increases as the temperature increases because ________.

The bond dissociation energy is the amount of energy required to break a bond ________.

In the first propagation step of the free radical chlorination of methane, which of the following occurs?

Given a K of 0.45 at 25°C, calculate the corresponding ΔG° in kJ/mol. [R = 8.314 J/K∙ mol]

Write an equation to describe the initiation step in the chlorination of methane.

Provide the major organic product(s) in the reaction below.

What is the hybridization of the negatively charged carbon in (CH3)3C:-?

Given a K of 2.2 at 25°C, calculate the corresponding ΔG° in kJ/mol. [R = 8.314 J/K∙ mol]

Predict the signs of ΔH° and ΔS° in the reaction of cyclohexene with H2 to form cyclohexane, shown below.

What is the CCC bond angle in (CH3)3C:-?

Given a reaction in which reactant A is converted only to product B at 25°C, what Keq results if at equilibrium 80% of A has become B?

Structure and Bonding

Acids and Bases; Functional Groups

Structure and Stereochemistry of Alkanes

Stereochemistry

Alkyl Halides; Nucleophilic Substitution

Structure and Synthesis of Alkenes; Elimination

Reactions of Alkenes

Structure and Synthesis of Alcohols

Reactions of Alcohols

Infrared Spectroscopy and Mass Spectrometry

Nuclear Magnetic Resonance Spectroscopy

Ethers, Epoxides, and Thioethers

Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy

Aromatic Compounds

Reactions of Aromatic Compounds

Ketones and Aldehydes

Amines

Carboxylic Acids

Carboxylic Acid Derivatives

Condensations and Alpha Substitutions of Carboxyl Compounds

Carbohydrates and Nucleic Acids

Amino Acids, Peptides, and Proteins

Lipids

Synthetic Polymers

Filters

Given a K of 0.45 at 25°C, calculate the corresponding ΔG°in kJ/mol. [R = 8.314 J/K∙ mol]

What is the hybridization of the negatively charged carbon in (CH₃)₃C:^-?

Given a K of 2.2 at 25°C, calculate the corresponding ΔG°in kJ/mol. [R = 8.314 J/K∙ mol]

Predict the signs of ΔH° and ΔS° in the reaction of cyclohexene with H₂ to form cyclohexane, shown below.

What is the CCC bond angle in (CH₃)₃C:^-?

Given a reaction in which reactant A is converted only to product B at 25°C, what K_eq results if at equilibrium 80% of A has become B?