Question 1

How many stereocenters are present in 3-methyl-2-pentanol?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  5 
A)  1 
B)  2 
C)  3 
D)  5

Question 2

Which statement is true of a carbon atom that is a stereocenter?

Accepted Answer

A)  It is bonded to two identical groups and two different groups by single bonds. 
B)  It has a double bond and two single bonds. 
C)  It is bonded to four different groups by single bonds. 
D)  It is bonded to two pairs of groups, with the groups of each pair being identical. 
A)  It is bonded to two identical groups and two different groups by single bonds. 
B)  It has a double bond and two single bonds. 
C)  It is bonded to four different groups by single bonds. 
D)  It is bonded to two pairs of groups, with the groups of each pair being identical.

Question 3

Which of the following classes of isomers has a pair of stereoisomers that are nonsuperposable mirror images?

Accepted Answer

A)  diastereomers 
B)  enantiomers 
C)  cis-trans isomers 
D)  constitutional isomers 
A)  diastereomers 
B)  enantiomers 
C)  cis-trans isomers 
D)  constitutional isomers

Question 4

Which of the following is a liver toxin?

Accepted Answer

A)  (R)-ibuprofen 
B)  (S)-ibuprofen 
C)  (R)-naproxen 
D)  (S)-naproxen 
A)  (R)-ibuprofen 
B)  (S)-ibuprofen 
C)  (R)-naproxen 
D)  (S)-naproxen

Question 5

How many stereocenters are present in the following compound?

Accepted Answer

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

Question 6

Which of the following molecules has an R configuration?

Accepted Answer

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

Question 7

The actual rotation of a sample measured in a 10 cm cell can be directly reported as the specific rotation if the concentration of the sample is which of the following?

Accepted Answer

A)  1 M 
B)  1 mg/L 
C)  1 g/mL 
D)  1 g/L 
A)  1 M 
B)  1 mg/L 
C)  1 g/mL 
D)  1 g/L

Question 8

Consider the following ball-and-stick model. Atoms other than carbon and hydrogen are indicated by the chemical symbol of the element.   Which carbon atom represents a stereocenter?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  None of them is a stereocenter. 
A)  1 
B)  2 
C)  3 
D)  4 
E)  None of them is a stereocenter.

Question 9

Given the compounds 2-methyl-1-pentene and 3-methyl-1-pentene, which of the following statements is true?

Accepted Answer

A)  Only 2-methyl-1-pentene is chiral. 
B)  Only 3-methyl-1-pentene is chiral. 
C)  Both are chiral. 
D)  Neither is chiral. 
A)  Only 2-methyl-1-pentene is chiral. 
B)  Only 3-methyl-1-pentene is chiral. 
C)  Both are chiral. 
D)  Neither is chiral.

Question 10

Which of the following is the correct order of priorities in the R,S system?

Accepted Answer

A)  alkyl > amino > hydroxyl > thiol 
B)  alkyl > hydroxyl > amino > thiol 
C)  thiol > amino > hydroxyl > alkyl 
D)  thiol > hydroxyl > amino > alkyl 
A)  alkyl > amino > hydroxyl > thiol 
B)  alkyl > hydroxyl > amino > thiol 
C)  thiol > amino > hydroxyl > alkyl 
D)  thiol > hydroxyl > amino > alkyl

Question 11

Consider the following two ball-and-stick models. Atoms other than carbon and hydrogen are indicated by the chemical symbol of the element.   Which of the following correctly describes the compound represented by these models?

Accepted Answer

A)  chiral 
B)  stereoisomers 
C)  enantiomers 
D)  all of these 
A)  chiral 
B)  stereoisomers 
C)  enantiomers 
D)  all of these

Question 12

In the R,S system, which of the following groups has the highest priority?

Accepted Answer

A)  alkyl 
B)  amino 
C)  hydroxyl 
D)  thiol 
A)  alkyl 
B)  amino 
C)  hydroxyl 
D)  thiol

Question 13

In its pyranose form, naturally occurring D-glucose has five stereocenters. How many possible stereoisomers exist for this structure?

Accepted Answer

A)  5 
B)  10 
C)  25 
D)  32 
A)  5 
B)  10 
C)  25 
D)  32

Question 14

Which statement is true regarding the optical activity of a pair of enantiomers?

Accepted Answer

A)  Each of its members rotates the plane of polarized light by unequal degrees in opposite directions. 
B)  Each of its members rotates the plane of polarized light by unequal degrees in the same direction. 
C)  Each of its members rotates the plane of polarized light by equal degrees in opposite directions. 
D)  Each of its members rotates the plane of polarized light by equal degrees in the same direction. 
A)  Each of its members rotates the plane of polarized light by unequal degrees in opposite directions. 
B)  Each of its members rotates the plane of polarized light by unequal degrees in the same direction. 
C)  Each of its members rotates the plane of polarized light by equal degrees in opposite directions. 
D)  Each of its members rotates the plane of polarized light by equal degrees in the same direction.

Question 15

Consider the following ball-and-stick model. Elements other than hydrogen and carbon are labeled.   Which of the following specifies the configuration at the stereocenter?

Accepted Answer

A)  R 
B)  S 
C)  Neither R nor S; there is no stereocenter in this compound. 
D)  Both R and S; there are two stereocenters in this compound. 
A)  R 
B)  S 
C)  Neither R nor S; there is no stereocenter in this compound. 
D)  Both R and S; there are two stereocenters in this compound.

Question 16

Which of the following is the correct order of priorities in the R,S system?

Accepted Answer

A)  aldehyde > carboxyl > ketone > primary alcohol 
B)  carboxyl > ketone > aldehyde > primary alcohol 
C)  primary alcohol > aldehyde > ketone > carboxyl 
D)  primary alcohol > ketone > carboxyl > aldehyde 
A)  aldehyde > carboxyl > ketone > primary alcohol 
B)  carboxyl > ketone > aldehyde > primary alcohol 
C)  primary alcohol > aldehyde > ketone > carboxyl 
D)  primary alcohol > ketone > carboxyl > aldehyde

Question 17

Which of the following correctly describes the relationship between the R,S system and the actual rotation associated with optically active compounds?

Accepted Answer

A)  All R enantiomers are dextrorotatory. 
B)  All S enantiomers are dextrorotatory. 
C)  No S enantiomers are dextrorotatory, but some R enantiomers are levorotatory. 
D)  There is no general relationship between the R,S designation and the actual direction of rotation of plane-polarized light. 
A)  All R enantiomers are dextrorotatory. 
B)  All S enantiomers are dextrorotatory. 
C)  No S enantiomers are dextrorotatory, but some R enantiomers are levorotatory. 
D)  There is no general relationship between the R,S designation and the actual direction of rotation of plane-polarized light.

Question 18

How many chiral stereoisomers are possible for the following triglyceride?

Accepted Answer

A)  2 
B)  4 
C)  8 
D)  32 
A)  2 
B)  4 
C)  8 
D)  32

Question 19

There are four alcohols with the molecular formula C4H9OH. How many of these are chiral?

Accepted Answer

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

Question 20

What is the maximum number of stereoisomers possible for a molecule that has three stereocenters (assuming no other structural features that lead to stereoisomerism exist)?

Accepted Answer

A)  2 
B)  4 
C)  8 
D)  16 
A)  2 
B)  4 
C)  8 
D)  16

Exam 14: Chirality: the Handedness of Molecules

How many stereocenters are present in 3-methyl-2-pentanol?

Which statement is true of a carbon atom that is a stereocenter?

Which of the following classes of isomers has a pair of stereoisomers that are nonsuperposable mirror images?

Which of the following is a liver toxin?

How many stereocenters are present in the following compound?

Which of the following molecules has an R configuration?

The actual rotation of a sample measured in a 10 cm cell can be directly reported as the specific rotation if the concentration of the sample is which of the following?

Consider the following ball-and-stick model. Atoms other than carbon and hydrogen are indicated by the chemical symbol of the element. Which carbon atom represents a stereocenter?

Given the compounds 2-methyl-1-pentene and 3-methyl-1-pentene, which of the following statements is true?

Which of the following is the correct order of priorities in the R,S system?

Consider the following two ball-and-stick models. Atoms other than carbon and hydrogen are indicated by the chemical symbol of the element. Which of the following correctly describes the compound represented by these models?

In the R,S system, which of the following groups has the highest priority?

In its pyranose form, naturally occurring D-glucose has five stereocenters. How many possible stereoisomers exist for this structure?

Which statement is true regarding the optical activity of a pair of enantiomers?

Consider the following ball-and-stick model. Elements other than hydrogen and carbon are labeled. Which of the following specifies the configuration at the stereocenter?

Which of the following is the correct order of priorities in the R,S system?

Which of the following correctly describes the relationship between the R,S system and the actual rotation associated with optically active compounds?

How many chiral stereoisomers are possible for the following triglyceride?

There are four alcohols with the molecular formula C4H9OH. How many of these are chiral?

What is the maximum number of stereoisomers possible for a molecule that has three stereocenters (assuming no other structural features that lead to stereoisomerism exist)?

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There are four alcohols with the molecular formula C₄H₉OH. How many of these are chiral?