Question 1

In 1,3,5-hexatriene, there are ________ nodes in the HOMO and ________ nodes in the LUMO for this molecule.

Accepted Answer

A)  1; 2 
B)  2; 3 
C)  2; 0 
D)  2; 1 
A)  1; 2 
B)  2; 3 
C)  2; 0 
D)  2; 1

Question 2

Anthocyanidins are the organic compounds largely responsible for the color of wine and grape juice. They can also be used as indicators in pH titrations. Given the reaction below, which form of the compound is colored and which is colorless.

Accepted Answer

The carbinal pseudobase form o

Question 3

Draw the structure of the major product which results when the diene shown is treated with HBr at -80°C.

Accepted Answer

The answer of Draw the structure of the major product...

Question 4

Draw the LUMO of pentadienyl cation.

Accepted Answer

The answer of Draw the LUMO of pentadienyl cation....

Question 5

Draw the HOMO of pentadienyl anion.

Accepted Answer

The answer of Draw the HOMO of pentadienyl anion....

Question 6

Absorption of UV-visible energy by a molecule results in ________.

Accepted Answer

A)  vibrational transitions 
B)  electronic transitions 
C)  rotational transitions 
D)  nuclear transitions 
E)  none of the above 
A)  vibrational transitions 
B)  electronic transitions 
C)  rotational transitions 
D)  nuclear transitions 
E)  none of the above

Question 7

Provide the structure of the major organic product in the following reaction.

Accepted Answer

The answer of Provide the structure of the major organic...

Question 8

Provide the two major organic products of the following reaction.

Accepted Answer

The answer of Provide the two major organic products of...

Question 9

Show how the carbon p orbitals overlap to form the LUMO of the allyl anion.

Accepted Answer

The answer of Show how the carbon p orbitals overlap...

Question 10

Provide the major organic product of the following reaction.

Accepted Answer

The answer of Provide the major organic product of the...

Question 11

When (S)-3-bromopent-1-ene is heated in water, which of the following compounds is not produced?

Accepted Answer

A)  (S)-pent-1-en-3-ol 
B)  (R)-pent-1-en-3-ol 
C)  pent-4-en-1-ol 
D)  (
E) -pent-2-en-1-ol 
E)  (Z)-pent-2-en-1-ol 
A)  (S)-pent-1-en-3-ol 
B)  (R)-pent-1-en-3-ol 
C)  pent-4-en-1-ol 
D)  (
E) -pent-2-en-1-ol 
E)  (Z)-pent-2-en-1-ol

Question 12

Is the thermal [4+2] cycloaddition between allyl anion and ethylene an allowed one? To answer, draw the HOMO of allyl anion and the LUMO of ethylene, and comment on the symmetry match of the two.

Accepted Answer

@#IMG-DLM& The cyclo

Question 13

When 1 mole of anhydrous HCl is reacted with excess 1,3-pentadiene, both the 1,2 and the 1,4-addition products are formed. Which of the following structures shown below is the least likely to be one of these products? (Note: When a chiral carbon is formed in this reaction a racemic mixture results, only one of the two possible enantiomers is shown.)

Accepted Answer

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

Question 14

In the addition of HBr to conjugated dienes, is the product which results from 1,2-addition or that which results from 1,4-addition typically the product of kinetic control?

Accepted Answer

The product of kinet

Question 15

Provide the major organic product of the following reaction.

Accepted Answer

The answer of Provide the major organic product of the...

Question 16

Provide the major organic product of the following reaction.

Accepted Answer

The answer of Provide the major organic product of the...

Question 17

Rank the following compounds in order of increasing heats of hydrogenation. (The smallest ΔH is first.)

Accepted Answer

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

Question 18

Provide a detailed, stepwise mechanism for the reaction shown below.

Accepted Answer

The answer of Provide a detailed, stepwise mechanism for the...

Question 19

Provide the structure of the major product which results from 1,4-addition of Br2 to the diene shown below.

Accepted Answer

Question 20

Which of the following represents the highest occupied molecular orbital for the conjugated pi system in Vitamin D3?

Accepted Answer

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

Exam 15: Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy

In 1,3,5-hexatriene, there are ________ nodes in the HOMO and ________ nodes in the LUMO for this molecule.

Anthocyanidins are the organic compounds largely responsible for the color of wine and grape juice. They can also be used as indicators in pH titrations. Given the reaction below, which form of the compound is colored and which is colorless.

Draw the structure of the major product which results when the diene shown is treated with HBr at -80°C.

Draw the LUMO of pentadienyl cation.

Draw the HOMO of pentadienyl anion.

Absorption of UV-visible energy by a molecule results in ________.

Provide the structure of the major organic product in the following reaction.

Provide the two major organic products of the following reaction.

Show how the carbon p orbitals overlap to form the LUMO of the allyl anion.

Provide the major organic product of the following reaction.

When (S)-3-bromopent-1-ene is heated in water, which of the following compounds is not produced?

Is the thermal [4+2] cycloaddition between allyl anion and ethylene an allowed one? To answer, draw the HOMO of allyl anion and the LUMO of ethylene, and comment on the symmetry match of the two.

In the addition of HBr to conjugated dienes, is the product which results from 1,2-addition or that which results from 1,4-addition typically the product of kinetic control?

Provide the major organic product of the following reaction.

Provide the major organic product of the following reaction.

Rank the following compounds in order of increasing heats of hydrogenation. (The smallest ΔH is first.)

Provide a detailed, stepwise mechanism for the reaction shown below.

Provide the structure of the major product which results from 1,4-addition of Br2 to the diene shown below.

Which of the following represents the highest occupied molecular orbital for the conjugated pi system in Vitamin D3?

Structure and Bonding

Acids and Bases; Functional Groups

Structure and Stereochemistry of Alkanes

The Study of Chemical Reactions

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

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

In 1,3,5-hexatriene, there are nodes in the HOMO and nodes in the LUMO for this molecule.

Provide the structure of the major product which results from 1,4-addition of Br₂ to the diene shown below.

Which of the following represents the highest occupied molecular orbital for the conjugated pi system in Vitamin D₃?