Question 1

How many stereocenters are present in the following carbohydrate?

Accepted Answer

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

Question 2

When the sample chamber of a polarimeter is empty, which of the following statements is true?

Accepted Answer

A)  The maximum transmission of light occurs when the axes of the polarizer and analyzer are parallel to each other. 
B)  The maximum transmission of light occurs when the axes of the polarizer and analyzer are perpendicular to each other. 
C)  The maximum transmission of light occurs when the axes of the polarizer and analyzer are at an angle of 120° to each other. 
D)  Since the instrument is empty, the positions of the polarizer and analyzer have no effect on the amount of light transmission. 
A)  The maximum transmission of light occurs when the axes of the polarizer and analyzer are parallel to each other. 
B)  The maximum transmission of light occurs when the axes of the polarizer and analyzer are perpendicular to each other. 
C)  The maximum transmission of light occurs when the axes of the polarizer and analyzer are at an angle of 120° to each other. 
D)  Since the instrument is empty, the positions of the polarizer and analyzer have no effect on the amount of light transmission.

Question 3

Consider the following ball-and-stick model. Atoms other than carbon and hydrogen are indicated by the chemical symbol of the element.   What is the correct name for this substance?

Accepted Answer

A)  (R)-2-butanol 
B)  (S)-2-butanol 
C)  2-butanol 
D)  cis-2-butanol 
A)  (R)-2-butanol 
B)  (S)-2-butanol 
C)  2-butanol 
D)  cis-2-butanol

Question 4

Given the compounds 1,1,3-trimethylcyclohexane and 1,1,4-trimethylcyclohexane, which of the following statements is true?

Accepted Answer

A)  Only 1,1,3-trimethylcyclohexane is chiral. 
B)  Only 1,1,4-trimethylcylcohexane is chiral. 
C)  Both are chiral. 
D)  Neither is chiral. 
A)  Only 1,1,3-trimethylcyclohexane is chiral. 
B)  Only 1,1,4-trimethylcylcohexane is chiral. 
C)  Both are chiral. 
D)  Neither is chiral.

Question 5

Which of the following statements is true of dextrorotatory compounds?

Accepted Answer

A)  They all rotate plane-polarized light in a clockwise direction. 
B)  They all rotate plane-polarized light in a counterclockwise direction. 
C)  They all rotate unpolarized light in a clockwise direction. 
D)  They all rotate unpolarized light in a counterclockwise direction. 
A)  They all rotate plane-polarized light in a clockwise direction. 
B)  They all rotate plane-polarized light in a counterclockwise direction. 
C)  They all rotate unpolarized light in a clockwise direction. 
D)  They all rotate unpolarized light in a counterclockwise direction.

Question 6

Illustrated here are the four stereoisomers of an amino acid that has two stereocenters. Which structure(s) is/are the diastereomer(s) of structure A?

Accepted Answer

A)  B only 
B)  C only 
C)  D only 
D)  B and D only 
A)  B only 
B)  C only 
C)  D only 
D)  B and D only

Question 7

Which of the following molecules does not have an S configuration at a stereocenter?

Accepted Answer

A)  ​
  
B)  ​
  
C)  ​
  
D)  All these molecules have an (S)-stereocenter. 
A)  ​
  
B)  ​
  
C)  ​
  
D)  All these molecules have an (S)-stereocenter.

Question 8

Given the compounds 2,3-dimethylpentane and 2,4-dimethylpentane, which of the following is true?

Accepted Answer

A)  Only 2,3-dimethylpentane is chiral. 
B)  Only 2,4-dimethylpentane is chiral. 
C)  Both are chiral. 
D)  Neither is chiral. 
A)  Only 2,3-dimethylpentane is chiral. 
B)  Only 2,4-dimethylpentane is chiral. 
C)  Both are chiral. 
D)  Neither is chiral.

Question 9

Consider the following ball-and-stick model. Elements other than hydrogen and carbon are labeled.   The specific rotation of this substance is +2.6°. Which of the following describes this substance?

Accepted Answer

A)  dextrorotatory 
B)  levorotatory 
C)  both dextrorotatory and levorotatory 
D)  none of these 
A)  dextrorotatory 
B)  levorotatory 
C)  both dextrorotatory and levorotatory 
D)  none of these

Question 10

Identify a true statement about the R,S system for specifying the configuration of a stereocenter.

Accepted Answer

A)  Priorities are assigned to groups based on atomic numbers; the group with the highest atomic number is assigned the highest priority. 
B)  Priorities are assigned to groups based on orientation in space; a group directed toward a viewer is assigned the highest priority. 
C)  Priorities are assigned to groups based on atomic number; the group with the lowest atomic number is given the highest priority. 
D)  Priorities are assigned to groups based on orientation in space; a group directed away from a viewer is assigned the highest priority. 
A)  Priorities are assigned to groups based on atomic numbers; the group with the highest atomic number is assigned the highest priority. 
B)  Priorities are assigned to groups based on orientation in space; a group directed toward a viewer is assigned the highest priority. 
C)  Priorities are assigned to groups based on atomic number; the group with the lowest atomic number is given the highest priority. 
D)  Priorities are assigned to groups based on orientation in space; a group directed away from a viewer is assigned the highest priority.

Question 11

Consider the following ball-and-stick model. Atoms other than carbon and hydrogen are indicated by the chemical symbol of the element.   Which of the following can also be used to specify the geometry of this substance?

Accepted Answer

A)  ​
  
B)  ​
  
C)  ​
  
D)  neither of these models 
E)  all of these models 
A)  ​
  
B)  ​
  
C)  ​
  
D)  neither of these models 
E)  all of these models

Question 12

Which of the following represents the enantiomer of the following compound?

Accepted Answer

A)  ​
  
B)  ​
  
C)  both   and
  
D)  none of these 
A)  ​
  
B)  ​
  
C)  both   and
  
D)  none of these

Exam 14: Chirality: the Handedness of Molecules

How many stereocenters are present in the following carbohydrate?

When the sample chamber of a polarimeter is empty, which of the following statements is true?

Consider the following ball-and-stick model. Atoms other than carbon and hydrogen are indicated by the chemical symbol of the element. What is the correct name for this substance?

Given the compounds 1,1,3-trimethylcyclohexane and 1,1,4-trimethylcyclohexane, which of the following statements is true?

Which of the following statements is true of dextrorotatory compounds?

Illustrated here are the four stereoisomers of an amino acid that has two stereocenters. Which structure(s) is/are the diastereomer(s) of structure A?

Which of the following molecules does not have an S configuration at a stereocenter?

Given the compounds 2,3-dimethylpentane and 2,4-dimethylpentane, which of the following is true?

Consider the following ball-and-stick model. Elements other than hydrogen and carbon are labeled. The specific rotation of this substance is +2.6°. Which of the following describes this substance?

Identify a true statement about the R,S system for specifying the configuration of a stereocenter.

Consider the following ball-and-stick model. Atoms other than carbon and hydrogen are indicated by the chemical symbol of the element. Which of the following can also be used to specify the geometry of this substance?

Which of the following represents the enantiomer of the following compound?

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