Deck 6: Chirality: the Handedness of Molecules

Question 1

Rank the following substituents in order of decreasing priority (highest first).

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

Answer 1

IV, I, II, III

Question 2

Which structure is correctly named 3S,4S-3,4-dimethylhexane ?

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

Answer 2

IV

Question 3

Which structures are chiral?

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

Answer 3

III, IV

Question 4

What is the relationship between these two structures?

A) Identical structures
B) Enantiomers
C) Diastereomers
D) Constitutional isomers

Question 5

Which forms of lactic acid are R forms?

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

Question 6

Rank the following substituents in order of increasing priority.

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

Question 7

Rank the following substituents in order of increasing priority.

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

Question 8

What is the relationship between these two structures?

A) Identical structures
B) Enantiomers
C) Diastereomers
D) Constitutional isomers

Question 9

Which compounds contain stereocenters?

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

Question 10

Rank the following substituents in order of increasing priority.

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

Question 11

How many stereoisomers are possible for 1,2-dichlorocyclopentane?

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

Question 12

Which pair of structures are enantiomers?

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

Question 13

Which structures represent R-3-methylhexane?
Help: Build the structures using a molecular model.

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

Question 14

What is the R,S configuration for the following structure of isocitric acid?

A) 2R, 3R
B) 2R, 3S
C) 2S, 3R
D) 2S, 3S

Question 15

Aspartame is an artificial, non-saccharide sweetener. It is made from two amino acids: phenylalanine (methyl ester) and aspartic acid. Both aminoacids have one stereocenter. Both stereocenters have S-stereoconfiguration. Which of the two structures is aspartame?

A) both structures are correct
B) I
C) II
D) Neither structure is correct.

Question 16

Which compounds contain stereocenters?
I. 1-chloropentane
II. 2-chloropentane
III. 3-chloropentane
IV. 1,2-dichloropentane

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

Question 17

Which compounds have multiple stereocenters?

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

Question 18

How many stereoisomers are possible for 2,3-butanediol?

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

Question 19

How many stereoisomers are possible for the following structure?

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

Question 20

Which compounds contain stereocenters?
I. 2-methylpentane
II. chlorocyclohexane
III. 3-methyl-2-butanol
IV. 2-hydroxypropanoic acid

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

Question 21

Which statements about stereoisomers are true? (Sec. 6.7, 6.8)
I. enantiomers and diastereomers have the same physical properties.
II. 50/50 mixtures of R and S enantiomers are called racemic mixtures.
III. meso isomers rotate the plane of plane polarized light.
IV. dextrorotatory compounds rotate plane polarized light to the right.

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

Question 22

The specific rotation of dextrorotatory tartaric acid is +12.7 degrees. A mixture of dextrorotatory and levorotatory tartaric acid has a specific rotation of +6.35 degrees. What is the optical purity of the mixture?

A) 25%
B) 33 1/3%
C) 50%
D) 75%

Question 23

What is the relationship between these two structures?

A) Identical structures
B) Enantiomers
C) Diastereomers
D) Constitutional isomers

Question 24

What is the relationship between these two structures?
HINT: Build the molecular models and compare!

A) Identical structures
B) Enantiomers
C) Diastereomers
D) Constitutional isomers

Question 25

What is the relationship between these two structures?

A) identical structures
B) enantiomers
C) diastereomers
D) constitutional isomers

Question 26

What is the relationship between these two structures?

A) Identical structures
B) Enantiomers
C) Diastereomers
D) Constitutional isomers

Question 27

The priority order for the following groups are (highest = 1),

Question 28

The priority order for the following groups is (highest = 1),

Question 29

Which statement about enantiomers is false?

A) enantiomers have the same boiling and melting points.
B) enantiomers have the same chemical properties in an achiral environment.
C) enantiomers have the same atom connectivity.
D) enantiomers have the same three dimensional orientation.

Question 30

Which are meso compounds?

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

Question 31

Which are meso compounds?

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

Question 32

How many stereoisomers are possible for Prilosec?

A) 0
B) 2
C) 4
D) 8

Question 33

Which are meso compounds?

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

Question 34

The structure of the S,S enantiomer of 2,3-butanediol is,

Question 35

Tuftsin (named after Tufts University) has important functions in the human immune system. It binds to stereospecific receptors at the surface of macrophages and leukocytes, stimulating their bactericidal and tumoricidal activity. All stereocenters in this molecule have S-configurations. How many stereoisomers of tuftsin exist, which do not have the correct stereochemistry for receptor-binding?

A) 7
B) 15
C) 31
D) 32

Question 36

The following structure is the _____________ configuration.

Question 37

How many pairs of enantiomers are possible for cholesterol?

A) 16
B) 32
C) 64
D) 128

Question 38

Which compound is a meso compound?

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

Question 39

The following structure is the _____________ configuration.

Question 40

How many pairs of enantiomers are possible for cortisone acetate?

A) 32
B) 64
C) 128
D) 256

Question 41

Hydrocodone, the synthetic opiate in Vicodin contains ______ stereocenters.

Question 42

The structure of the 3S,4R enantiomer of 3-bromo-4-chlorohexane is,

Question 43

The following structure contains ………..stereocenters.

Question 44

The following structure contains ___________ stereocenters.

Question 45

The following structures are diastereomers.

Question 46

2R,4R-2-bromo-4-chloropentane and 2S,4S-2-bromo-4-chloropentane are meso compounds.

Question 47

Enantiomers have the same physical properties (m.p., b.p., density).

Question 48

Glutathione is an antioxidant, which helps to protect our cells from oxidative damage. Assign R or S configurations to the stereocenters I and II

Question 49

The following structure contains??____stereocenters.

Question 50

The following structures are enantiomers.

Question 51

The diastereomer of 2R,3R-dichlorobutane is achiral.

Question 52

The name of the following structure is 2S,3S-2,3-dibromobutane.

Question 53

Meso compounds rotate plane polarized light the same magnitude as enantiomers, but in opposite directions.

Question 54

The following structure contains __________ stereocenters.

Question 55

The following groups are listed in decreasing order of priority.

Question 56

The following groups are listed in decreasing order of priority.

Question 57

The following structures are __________________ (what type of stereoisomer?).

Question 58

The following structures are ________________ (what type of stereoisomer).

Question 59

The diastereomers 2S,4R-2-bromo-4-chloropentane and 2S,4S-2-bromo-4-chloropentane are achiral.