Question 1

Absorption of UV-visible radiation by a molecule results in___________ transitions.

Accepted Answer

A) electronic 
B) nuclear 
C) rotational 
D) vibrational 
E) None of these 
A) electronic 
B) nuclear 
C) rotational 
D) vibrational 
E) None of these

Question 2

Which one of the following dienes will have the highest heat of hydrogenation?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
E) V 
A) I 
B) II 
C) III 
D) IV 
E) V

Question 3

Which one of the following dienes is least stable?

Accepted Answer

A) CH3CH=CHCH=CHCH3 
B) CH3CH=CHCH2CH=CH2 
C) CH2=CHCH2CH2CH=CH2 
D) CH2=CHCH(CH3)CH=CH2 
E) CH3CH=C=CHCH2CH3 
A) CH3CH=CHCH=CHCH3 
B) CH3CH=CHCH2CH=CH2 
C) CH2=CHCH2CH2CH=CH2 
D) CH2=CHCH(CH3)CH=CH2 
E) CH3CH=C=CHCH2CH3

Question 4

Predict the major product for the following reaction.

Accepted Answer

The answer of Predict the major product for the following...

Question 5

Rank the following dienes in order of decreasing heat of hydrogenation (most to least).

Accepted Answer

The answer of Rank the following dienes in order of...

Question 6

Predict the product(s)for the following reaction.

Accepted Answer

The answer of Predict the product(s)for the following reaction. ...

Question 7

Rank the following dienes in order of decreasing heat of hydrogenation (most to least).

Accepted Answer

The answer of Rank the following dienes in order of...

Question 8

A reaction under kinetic control will yield :

Accepted Answer

A) the most stable product. 
B) the product that can be formed in the fewest steps. 
C) the product whose formation requires the smallest free energy of activation. 
D) the product with the greatest potential energy. 
E) None of these 
A) the most stable product. 
B) the product that can be formed in the fewest steps. 
C) the product whose formation requires the smallest free energy of activation. 
D) the product with the greatest potential energy. 
E) None of these

Question 9

Predict the possible major products for the following reaction.

Accepted Answer

The answer of Predict the possible major products for the...

Question 10

Which one of the following dienes is least stable?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
A) I 
B) II 
C) III 
D) IV

Question 11

Which one of the following represents the highest energy  $\pi$-antibonding molecular orbital of 1,3-butadiene?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
A) I 
B) II 
C) III 
D) IV

Question 12

Predict the major product for the following reaction and explain why it is major product.

Accepted Answer

@#IMG-DLM& 1,4-product is the major one

Question 13

A thermodynamically-controlled reaction will yield :

Accepted Answer

A) the most stable product. 
B) the product whose formation requires the smallest free energy of activation. 
C) the product that can be formed in the fewest steps. 
D) the product that is formed at the fastest rate. 
E) None of these. 
A) the most stable product. 
B) the product whose formation requires the smallest free energy of activation. 
C) the product that can be formed in the fewest steps. 
D) the product that is formed at the fastest rate. 
E) None of these.

Question 14

Which of the following compound(s)have the longest $\lambda$max?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
E) V 
A) I 
B) II 
C) III 
D) IV 
E) V

Question 15

How many electrons does the HOMO of 1,3-pentadiene have in its excited state?

Accepted Answer

A) 1 
B) 2 
C) 3 
D) 4 
E) none 
A) 1 
B) 2 
C) 3 
D) 4 
E) none

Question 16

Which is the most energetically favorable UV transition for 1,3-butadiene?.

Accepted Answer

A) n $\rightarrow$ $\sigma$* 
B) n $\rightarrow$ $\pi$* 
C) . $\pi$2  $\rightarrow$$\pi$3* 
D) .$\sigma$ $\rightarrow$ $\sigma$* 
E) . $\pi$1  $\rightarrow$$\pi$4* 
A) n $\rightarrow$ $\sigma$* 
B) n $\rightarrow$ $\pi$* 
C) . $\pi$2  $\rightarrow$$\pi$3* 
D) .$\sigma$ $\rightarrow$ $\sigma$* 
E) . $\pi$1  $\rightarrow$$\pi$4*

Question 17

Which one of the following represents the lowest energy  $\pi$-bonding molecular orbital of 1,3-butadiene?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
A) I 
B) II 
C) III 
D) IV

Question 18

Predict the major product for the following reaction.

Accepted Answer

The answer of Predict the major product for the following...

Question 19

Which one of the following represents the HOMO of 1,3,5-hexatriene?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
E) V 
A) I 
B) II 
C) III 
D) IV 
E) V

Question 20

How many electrons does the HOMO of 2,4-hexadiene have in its ground state?

Accepted Answer

A) 1 
B) 2 
C) 3 
D) 4 
E) 0 
A) 1 
B) 2 
C) 3 
D) 4 
E) 0

Exam 17: Conjugated Pi Systems and Pericyclic Reactions

Absorption of UV-visible radiation by a molecule results in___________ transitions.

Which one of the following dienes will have the highest heat of hydrogenation?

Which one of the following dienes is least stable?

Predict the major product for the following reaction.

Rank the following dienes in order of decreasing heat of hydrogenation (most to least).

Predict the product(s)for the following reaction.

Rank the following dienes in order of decreasing heat of hydrogenation (most to least).

A reaction under kinetic control will yield :

Predict the possible major products for the following reaction.

Which one of the following dienes is least stable?

Which one of the following represents the highest energy π\piπ -antibonding molecular orbital of 1,3-butadiene?

Predict the major product for the following reaction and explain why it is major product.

A thermodynamically-controlled reaction will yield :

Which of the following compound(s)have the longest λ\lambdaλ max?

How many electrons does the HOMO of 1,3-pentadiene have in its excited state?

Which is the most energetically favorable UV transition for 1,3-butadiene?.

Which one of the following represents the lowest energy π\piπ -bonding molecular orbital of 1,3-butadiene?

Predict the major product for the following reaction.

Which one of the following represents the HOMO of 1,3,5-hexatriene?

How many electrons does the HOMO of 2,4-hexadiene have in its ground state?

A Review of General Chemistry: Electrons, Bonds, and Molecular Properties

Molecular Representations

Acids and Bases

Alkanes and Cycloalkanes

Stereoisomerism

Chemical Reactivity and Mechanisms

Substitution Reactions

Alkenes: Structure and Preparation Via Elimination Reactions

Addition Reactions of Alkenes

Alkynes

Radical Reactions

Synthesis

Alcohols and Phenols

Ethers and Epoxides; Thiols and Sulfides

Nuclear Magnetic Resonance Spectroscopy

Infrared Spectroscopy and Mass Spectrometry

Aromatic Compounds

Aromatic Substitution Reactions

Aldehydes and Ketones

Carboxylic Acids and Their Derivatives

Alpha Carbon Chemistry: Enols and Enolates

Amines

Carbohydrates

Amino Acids, Peptides, and Proteins

Lipids

Synthetic Polymers

Filters

Which one of the following represents the highest energy $\pi$ -antibonding molecular orbital of 1,3-butadiene? $Which one of the following represents the highest energy \pi -antibonding molecular orbital of 1,3-butadiene?$

Which of the following compound(s)have the longest $\lambda$ _max? $Which of the following compound(s)have the longest \lambda <sub>max</sub>?$

Which one of the following represents the lowest energy $\pi$ -bonding molecular orbital of 1,3-butadiene? $Which one of the following represents the lowest energy \pi -bonding molecular orbital of 1,3-butadiene?$