Question 1

The molar absorptivity of ethylene in hexane is 15,000 L mol−1 cm−1. What is the maximum absorbance observed at a concentration of 1.5 x 10−4 mol L−1? (Path length = 1 cm)

Accepted Answer

A)   2.25
B)   1.25
C)   3.25
D)   2.52E) A) and B)
F) B) and C)

Question 2

What is (are)  the major organic product(s)  formed in the following reaction?

Accepted Answer

A)   only 1
B)   only 1 and 3
C)   only 2 and 4
D)   only 1 and 4E) All of the above
F) A) and B)

Question 3

What is the kinetic product obtained from the addition of 1 mole of bromine to 1,3-butadiene?

Accepted Answer

A)   3,4-dibromo-1-butene
B)   (
E)  -1,4-dibromo-2-butene
C)   (Z) -1,4-dibromo-2-butene
D)   (Z) -2,3-dibromo-2-buteneE) All of the above
F) A) and B)

Question 4

Which of the following has the highest value of λmax in the ultraviolet-visible spectrum? max in the ultraviolet-visible spectrum?   A)  1 B)  2 C)  3 D)  4" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   1
B)   2
C)   3
D)   4E) C) and D)
F) A) and C)

Question 5

When an organic molecule is irradiated with ultraviolet radiation, the energy absorbed by the molecule corresponds to the amount necessary to excite electrons from one molecular orbital to another.

Accepted Answer

A) True 
 B)False

Question 6

Consider the reaction below to answer the following question(s):  Enter the appropriate letter in the blank for each the following statements.
-The product that results from following mechanistic step is _____.

Accepted Answer

The answer of Consider the reaction below to answer the...

Question 7

Consider the reaction below to answer the following question(s):  Enter the appropriate letter in the blank for each the following statements.
-The nucleophile in this reaction is ____.

Accepted Answer

The answer of Consider the reaction below to answer the...

Question 8

Consider the following reaction.  This is an example of a sigmatropic reaction with a [3,3]-shift.

Accepted Answer

A) True 
 B)False

Question 9

The [2+2] cycloaddition reaction of ethylene to form cyclobutane does not occur because _____. ​

Accepted Answer

A)   the reaction is forbidden as determined by the frontier molecular orbital analysis
B)   the reaction is allowed as determined by the frontier molecular orbital analysis
C)   the reaction is allowed, and ethylene collides in a suprafacial manner
D)   the reaction is allowed, and ethylene collides in an antarafacial mannerE) B) and C)
F) B) and D)

Question 10

What is the major organic product obtained from the following reaction?

Accepted Answer

The answer of What is the major organic product obtained...

Question 11

Draw two resonance structures of the reactive intermediate that accounts for the formation of 1,2- and 1,4-addition products upon reaction of 1,3-butadiene with one equivalent of bromine.

Accepted Answer

The answer of Draw two resonance structures of the reactive...

Question 12

Which of the following relationships is not valid as applied to ultraviolet-visible spectroscopy?

Accepted Answer

A)   A = log (Io/I) 
B)   A = εcl
C)   ΔE = hν
D)   A = λmaxlE) All of the above
F) None of the above

Question 13

Which of the following energy diagrams represents the electronic state of butadiene after absorption of radiation?

Accepted Answer

A)   1
B)   2
C)   3
D)   4E) B) and C)
F) A) and B)

Question 14

What quantity is abbreviated as ε in ultraviolet-visible spectroscopy?

Accepted Answer

A)   absorbance
B)   molecular absorptivity
C)   intensity of transmitted light
D)   wavelength of maximum absorbanceE) B) and C)
F) None of the above

Question 15

What is the reactive intermediate in the reaction of 1,3-butadiene with HBr resulting in 1,2-addition?

Accepted Answer

A)   cyclic bromonium cation
B)   allylic cation
C)   allylic radical
D)   dienophileE) A) and B)
F) B) and C)

Exam 20: Dienes, Conjugated Systems, and Pericyclic Reactions

Consider the following reaction. This is an example of a sigmatropic reaction with a [3,3]-shift.

Correct Answer
verified

When an organic molecule is irradiated with ultraviolet radiation, the energy absorbed by the molecule corresponds to the amount necessary to excite electrons from one molecular orbital to another.

Correct Answer
verified

Which of the following has the highest value of λ_max in the ultraviolet-visible spectrum?

Correct Answer
verified

Consider the reaction below to answer the following question(s): Enter the appropriate letter in the blank for each the following statements. -The nucleophile in this reaction is ____.

Correct Answer
verified

What quantity is abbreviated as ε in ultraviolet-visible spectroscopy?

Correct Answer
verified

Which of the following relationships is not valid as applied to ultraviolet-visible spectroscopy?

Correct Answer
verified

What is the major organic product obtained from the following reaction?

Correct Answer
verified

What is (are) the major organic product(s) formed in the following reaction?

Correct Answer
verified

The molar absorptivity of ethylene in hexane is 15,000 L mol⁻¹ cm⁻¹. What is the maximum absorbance observed at a concentration of 1.5 x 10⁻⁴ mol L⁻¹? (Path length = 1 cm)

Correct Answer
verified

What is the reactive intermediate in the reaction of 1,3-butadiene with HBr resulting in 1,2-addition?

Correct Answer
verified

What is the kinetic product obtained from the addition of 1 mole of bromine to 1,3-butadiene?

Correct Answer
verified

Draw two resonance structures of the reactive intermediate that accounts for the formation of 1,2- and 1,4-addition products upon reaction of 1,3-butadiene with one equivalent of bromine.

Correct Answer
verified

The [2+2] cycloaddition reaction of ethylene to form cyclobutane does not occur because _____.

Correct Answer
verified

Which of the following energy diagrams represents the electronic state of butadiene after absorption of radiation?

Correct Answer
verified

Consider the reaction below to answer the following question(s): Enter the appropriate letter in the blank for each the following statements. -The product that results from following mechanistic step is _____.

Correct Answer
verified

Exam 20: Dienes, Conjugated Systems, and Pericyclic Reactions

Consider the following reaction. This is an example of a sigmatropic reaction with a [3,3]-shift.

Correct AnswerverifiedShow Answer

When an organic molecule is irradiated with ultraviolet radiation, the energy absorbed by the molecule corresponds to the amount necessary to excite electrons from one molecular orbital to another.

Correct AnswerverifiedShow Answer

Which of the following has the highest value of λmax in the ultraviolet-visible spectrum?

Correct AnswerverifiedShow Answer

Consider the reaction below to answer the following question(s): Enter the appropriate letter in the blank for each the following statements. -The nucleophile in this reaction is ____.

Correct AnswerverifiedShow Answer

What quantity is abbreviated as ε in ultraviolet-visible spectroscopy?

Correct AnswerverifiedShow Answer

Which of the following relationships is not valid as applied to ultraviolet-visible spectroscopy?

Correct AnswerverifiedShow Answer

What is the major organic product obtained from the following reaction?

Correct AnswerverifiedShow Answer

What is (are) the major organic product(s) formed in the following reaction?

Correct AnswerverifiedShow Answer

The molar absorptivity of ethylene in hexane is 15,000 L mol−1 cm−1. What is the maximum absorbance observed at a concentration of 1.5 x 10−4 mol L−1? (Path length = 1 cm)

Correct AnswerverifiedShow Answer

What is the reactive intermediate in the reaction of 1,3-butadiene with HBr resulting in 1,2-addition?

Correct AnswerverifiedShow Answer

What is the kinetic product obtained from the addition of 1 mole of bromine to 1,3-butadiene?

Correct AnswerverifiedShow Answer

Draw two resonance structures of the reactive intermediate that accounts for the formation of 1,2- and 1,4-addition products upon reaction of 1,3-butadiene with one equivalent of bromine.

Correct AnswerverifiedShow Answer

The [2+2] cycloaddition reaction of ethylene to form cyclobutane does not occur because _____. ​

Correct AnswerverifiedShow Answer

Which of the following energy diagrams represents the electronic state of butadiene after absorption of radiation?

Correct AnswerverifiedShow Answer

Consider the reaction below to answer the following question(s): Enter the appropriate letter in the blank for each the following statements. -The product that results from following mechanistic step is _____.

Correct AnswerverifiedShow Answer

Correct Answer
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Correct Answer
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Which of the following has the highest value of λ_max in the ultraviolet-visible spectrum?

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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The molar absorptivity of ethylene in hexane is 15,000 L mol⁻¹ cm⁻¹. What is the maximum absorbance observed at a concentration of 1.5 x 10⁻⁴ mol L⁻¹? (Path length = 1 cm)

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

The [2+2] cycloaddition reaction of ethylene to form cyclobutane does not occur because _____.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified