Question 1

Which of the following laws relates absorbance to the concentration of a sample and the pathlength in ultraviolet-visible spectroscopy?

Accepted Answer

A)  Buzz-Beer law
B)  Beer-Lambert law
C)  Duff-Beer law
D)  Christopher-Lambert lawE) None of the above
F) B) and D)

Question 2

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 3

What is the systematic IUPAC name of the following compound?

Accepted Answer

A)  (3S,4
E)  -3-ethyl-3,4-dimethyl-1,4-hexadiene
B)  (3R,4
E)  -3-ethyl-3,4-dimethyl-1,4-hexadiene
C)  (3S,4Z) -3-ethyl-3,4-dimethyl-1,4-hexadiene
D)  (3R,4Z) -3-ethyl-3,4-dimethyl-1,4-hexadieneE) None of the above
F) All of the above

Question 4

Which of the following electronic transitions is (are)  apparent in the ultraviolet-visible spectrum of acrolein, H2C=CHCHO?
1) n   →\rarr→   π\piπ *
2)  π\piπ    →\rarr→   π\piπ *
3)   σ\sigmaσ→\rarr→   π\piπ *

Accepted Answer

A)  only 1
B)  only 2
C)  only 1 and 2
D)  1, 2 and 3 E) B) and C)
F) A) and D)

Question 5

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

Accepted Answer

A)  absorbance
B)  molecular absorptivity
C)  intensity of transmitted light
D)  wavelength of maximum absorbance E) All of the above
F) A) and B)

Question 6

Which of 1,3-cyclohexadiene and 1,4-cyclohexadiene has the greatest heat of hydrogenation (i.e., the most exothermic reaction with H2 in the presence of a catalyst). Provide a brief explanation for your choice ?

Accepted Answer

1,4-Cyclohexadiene has a great...

Question 7

What is the correct order of exothermicity for hydrogenation of the following hexadienes upon treatment with H2/Pd (more exothermic > less exothermic) ? 2/Pd (more exothermic > less exothermic) ?   A) 1 > 2 > 3 B) 3 > 1 > 2 C) 2 > 1 > 3 D) 3 > 2 > 1" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

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

Question 8

What are the two major organic products obtained from the following reaction?

Accepted Answer

The answer of What are the two major organic products...

Question 9

Which of the following reaction coordinate diagrams explains the formation of different thermodynamic (T)  and kinetic products from the same reactants (R) ?

Accepted Answer

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

Question 10

The following two compounds could be easily distinguished by NMR, IR, UV or MS spectra.

Accepted Answer

A) True 
 B)False

Question 11

The following compound could act as a diene in a Diels-Alder reaction.

Accepted Answer

A) True 
 B)False

Question 12

Consider the following structure.  This substance could be produced by the reaction of the following diene and dienophile.

Accepted Answer

A) True 
 B)False

Question 13

Which of the following is(are)  formed upon addition of 1 mol of Br2 to 1,3-cyclohexane? 2 to 1,3-cyclohexane?   A) only 2 B) only 1 and 3 C) only 2 and 4 D) 1, 2 and 3" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  only 2
B)  only 1 and 3
C)  only 2 and 4
D)  1, 2 and 3E) None of the above
F) All of the above

Question 14

What are the units of absorbance, A, in ultraviolet-visible spectroscopy?

Accepted Answer

A)  J.mol-1
B)  nm.mol-1
C)  J.mol-1.M-1
D)  none, A is a dimensionless quantityE) A) and B)
F) A) and C)

Question 15

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 16

Which of the following energy diagrams represents the electronic state of the ground state of 1,3-butadiene?

Accepted Answer

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

Question 17

What is the IUPAC name of the following compound?

Accepted Answer

(E)-2,3-di...

Question 18

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

Accepted Answer

A)  A
B)  B
C)  C
D)  DE) A) and B)
F) All of the above

Question 19

Provide the structures of the constitutional isomers of the two major organic products obtained from the following reaction?

Accepted Answer

The answer of Provide the structures of the constitutional isomers...

Question 20

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 HBr.

Accepted Answer

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

Exam 20: Dienes, Conjugated Systems, and Pericyclic Reactions

Consider the following structure. This substance could be produced by the reaction of the following diene and dienophile.

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

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The following two compounds could be easily distinguished by NMR, IR, UV or MS spectra.

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Which of the following electronic transitions is (are) apparent in the ultraviolet-visible spectrum of acrolein, H2C=CHCHO? 1) n →\rarr→ π\piπ * 2) π\piπ →\rarr→ π\piπ * 3) σ\sigmaσ→\rarr→ π\piπ *

Correct AnswerverifiedShow Answer

The following compound could act as a diene in a Diels-Alder reaction.

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Which of the following is(are) formed upon addition of 1 mol of Br2 to 1,3-cyclohexane?

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

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What are the two major organic products obtained from the following reaction?

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What is the IUPAC name of the following compound?

Correct Answerverified(E)-2,3-di...View AnswerShow 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.

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What is the correct order of exothermicity for hydrogenation of the following hexadienes upon treatment with H2/Pd (more exothermic > less exothermic) ?

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What is the systematic IUPAC name of the following compound?

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Which of the following reaction coordinate diagrams explains the formation of different thermodynamic (T) and kinetic products from the same reactants (R) ?

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Which of the following laws relates absorbance to the concentration of a sample and the pathlength in ultraviolet-visible spectroscopy?

Correct AnswerverifiedShow Answer

Which of the following energy diagrams represents the electronic state of the ground state of 1,3-butadiene?

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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 HBr.

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Provide the structures of the constitutional isomers of the two major organic products obtained from the following reaction?

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Which of 1,3-cyclohexadiene and 1,4-cyclohexadiene has the greatest heat of hydrogenation (i.e., the most exothermic reaction with H2 in the presence of a catalyst). Provide a brief explanation for your choice ?

Correct Answerverified1,4-Cyclohexadiene has a great...View AnswerShow Answer

What are the units of absorbance, A, in ultraviolet-visible spectroscopy?

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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.

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What quantity is abbreviated as $\varepsilon$ in ultraviolet-visible spectroscopy?

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Which of the following electronic transitions is (are) apparent in the ultraviolet-visible spectrum of acrolein, H₂C=CHCHO? 1) n $\rarr$ $\pi$ * 2) $\pi$ $\rarr$ $\pi$ * 3) $\sigma$ $\rarr$ $\pi$ *

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Which of the following is(are) formed upon addition of 1 mol of Br₂ to 1,3-cyclohexane?

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(E)-2,3-di...
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What is the correct order of exothermicity for hydrogenation of the following hexadienes upon treatment with H₂/Pd (more exothermic > less exothermic) ?

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Which of 1,3-cyclohexadiene and 1,4-cyclohexadiene has the greatest heat of hydrogenation (i.e., the most exothermic reaction with H₂ in the presence of a catalyst). Provide a brief explanation for your choice ?

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1,4-Cyclohexadiene has a great...
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