Deck 4: Isomers: the Arrangement of Atoms in Space

Question 1

Identify the compounds that are not chiral.

A)
B)
C)
D)

Answer 1

Question 2

Identify the pair of compounds.

A)identical
B)conformational isomers
C)constitutional isomers
D)configurational isomers
E)none of the above

Answer 2

configurational isomers

Question 3

Give the number of asymmetric centers in limonene.

A)2
B)3
C)1
D)5
E)4

Answer 3

1

Question 4

What is the relationship between the following compounds?

A)configurational isomers
B)conformational isomers
C)constitutional isomers
D)structural isomers
E)positional isomers

Question 5

Is the molecule shown below chiral or achiral?

Question 6

Is the molecule shown below chiral or achiral?

Question 7

How many asymmetric centers are present in a molecule of 2,4,6-trimethylheptane?

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

Question 8

Which of the following compounds is chiral?

A)
B)
C)
D)
E)

Question 9

Identify the compound(s)with asymmetric centers.

A)
B)
C)
D)
E)

Question 10

What is the relationship between the structures shown below?

A)diastereomers
B)constitutional isomers
C)conformational isomers
D)configurational isomers
E)enantiomers

Question 11

Is the molecule shown below chiral or achiral?

Question 12

What is the relationship between the structures shown below?

A)not isomers
B)constitutional isomers
C)conformational isomers
D)configurational isomers
E)enantiomers

Question 13

Which of the following compounds has an asymmetric center?

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

Question 14

How many asymmetric centers are present in the compound below?

Question 15

Which of the following cannot exhibit chirality?

A)2,3-dibromobutane
B)1,3-dibromobutane
C)1,2-dichlorobutane
D)1,4-dibromobutane
E)1-bromo-2-chlorobutane

Question 16

Identify the pair of compounds.

A)identical
B)conformation isomers
C)constitutional isomers
D)configurational isomers
E)none of the above

Question 17

What is the relationship between the following compounds?

A)constitutional isomers
B)enantiomers
C)diastereomers
D)conformational isomers
E)superimposable without bond rotation

Question 18

How many asymmetric centers are present in the compound shown below?

A)1
B)2
C)3
D)4
E)5

Question 19

Is the molecule shown below chiral or achiral?

Question 20

What type of isomers are CH₃CH₂OCH₃ and CH₃CH₂CH₂OH?

A)constitutional
B)symmetrical
C)configurational
D)conformational
E)stereochemical

Question 21

Which of the following compounds has an S configuration?

A)
B)
C)
D)
E)

Question 22

Which of the following compounds is an enantiomer of the structure below?

A)
B)
C)
D)A and B
E)It does not have an enantiomer.

Question 23

Identify the following compounds as R or S.

A)R,S,R
B)S,R,R
C)S,S,S
D)R,R,R
E)S,S,R

Question 24

Identify all pairs of enantiomers.

A)B and D,A and C
B)A and C
C)B and D
D)A and B,A and D,B and C,C and D
E)B and D,A and B,A and D,B and C,C and D

Question 25

Provide the structure of (R)-4-octanol.Be careful to indicate proper stereochemistry.

Question 26

The compound CH₃CHClCH₂CH=CHCH₂CH₃ contains only one asymmetric center.Explain why it has four stereoisomers.

Question 27

Which of the following groups has the highest priority using the Cahn,Ingold,Prelog rules?

A)
B)
C)-OH
D)-O-CH₃
E)

Question 28

Which of the following statements correctly describes the molecule shown below?

A)It is achiral.
B)It is meso.
C)Its asymmetric center possesses the R configuration.
D)The mirror image of this molecule is its enantiomer.
E)The molecule possesses enantiotopic hydrogens.

Question 29

Label each asymmetric center in the compound below as R or S.

Question 30

A and B are stereoisomers.They are nonsuperimposable and are mirror images of one another.Which of the following best describes the relationship between A and B?

A)structural isomers
B)enantiomers
C)conformational isomers
D)diastereomers
E)constitutional isomers

Question 31

The configuration of R-(+)-glyceraldehyde is as follows: What is the absolute configuration of (-)-lactic acid?

A)R configuration
B)L configuration
C)S configuration
D)R and S configuration
E)D and L configuration

Question 32

Identify the following compounds as R or S.

A)S,S,R
B)S,R,S
C)R,S,S
D)S,S,S
E)R,R,R

Question 33

Draw the structure of (S)-1-bromo-1-chloropropane.Take particular care to indicate three-dimensional stereochemistry detail properly.

Question 34

Indicate whether each of the following structures has the R or S configuration.What is the relationship between the two structures?

Question 35

Which of the following terms best describes the pair of compounds shown: enantiomers,diastereomers,or the same compound?

Question 36

What is the relationship between the structures shown below?

A)enantiomers
B)diastereomers
C)configurational isomers
D)identical compounds
E)constitutional isomers

Question 37

Draw the enantiomer of the compound below.

Question 38

Choose the enantiomer of the compound below.

A)
B)
C)
D)
E)

Question 39

Identify all identical compounds.

A)B and D,A and C
B)A and C
C)B and D
D)A and B,A and D,B and C,C and D
E)B and D,A and B,A and D,B and C,C and D

Question 40

Which of the following compounds has an R configuration?

A)
B)
C)
D)
E)

Question 41

Label each asymmetric center as R or S.

Question 42

Provide a careful structure for (2R,3S,4S)-2-bromo-4-methyl-3-hexanol.

Question 43

(-)-Mandelic acid has a specific rotation of -158°.What would be the specific rotation of a solution which contains 40% (-)-mandelic acid and 60% (+)-mandelic acid?

A)+95°
B)+63°
C)+32°
D)-32°
E)-63°

Question 44

A mixture of equal amounts of two enantiomers

A)is called a racemic mixture.
B)is optically inactive.
C)implies that the enantiomers are meso forms.
D)both A and B.
E)none of the above

Question 45

Which of the following is/are optically inactive?

A)a 50-50 mixture of R and S enantiomers
B)a meso compound
C)every achiral compound
D)a racemic mixture
E)all the above

Question 46

Provide a careful structure for (2S,3S)-2,3-dibromohexane.

Question 47

A sample of (+)and (-)-3-chlorohexane has a rotation of -20 degrees.Pure (+)-3-chlorohexane has a rotation of +40 degrees.Calculate the enantiomeric excess and the amount of (-)and (+)-3-chlorohexane in the original sample.

Question 48

Provide a careful structure for (2S,3R)-2,3-dibromohexane.

Question 49

If (S)-glyceraldehyde has a specific rotation of -8.7°,what is the specific rotation of (R)-glyceraldehyde?

A)-8.7°
B)+8.7°
C)0)0°
D)cannot be determined from the information given

Question 50

Which of the following is a true statement?

A)All chiral molecules possess a plane of symmetry.
B)All achiral molecules are meso.
C)All molecules which possess a single chirality center of the S configuration are levorotatory.
D)A mixture of achiral compounds will be optically inactive.
E)All molecules which possess two or more chirality centers will be chiral.

Question 51

Provide a careful structure for (2R,3S)-2,3-dibromohexane.

Question 52

A solution containing 0.96 g of 2-bromooctane in 10 mL ether solution gave an observed rotation of -1.8° in a 10 cm cell at 20°C.Calculate the specific rotation of this solution.

Question 53

Which of the following is not true of enantiomers?

A)They have the same melting point.
B)They have the same boiling point.
C)They have the same chemical reactivity with non-chiral reagents.
D)They have the same density.
E)They have the same specific rotation.

Question 54

Twenty grams of a compound was dissolved in 100 mL of solvent and gave an observed rotation of -20 degrees.The sample tube is 4 dm long.Calculate the specific rotation.

Question 55

Which of the following statements correctly pertains to a pair of enantiomers?

A)They rotate the plane of polarized light by exactly the same amount and in opposite directions.
B)They rotate the plane of polarized light by differing amounts and in opposite directions.
C)They rotate the plane of polarized light by differing amounts and in the same direction.
D)They have different melting points.
E)They have the same melting point,but they have different boiling points.

Question 56

The specific rotation of (R)-(+)-glyceraldehyde is +8.7°.If a mixture of glyceraldehydes enantiomers is 80% S and 20% R,what is the specific rotation of the mixture?

Question 57

The specific rotation of a pure substance is -5.90°.What is the percentage of this isomer in a mixture with an observed specific rotation of -2.95°?

A)25%
B)50%
C)75%
D)80%
E)0%

Question 58

Provide a careful structure for (2S,3R,4R)-2-bromo-4-methyl-3-hexanol.

Question 59

The specific rotation of a pure substance is 1.68°.What is the specific rotation of a mixture containing 75% of this isomer and 25% of the (-)isomer?

A)+1.68°
B)0°
C)+1.26°
D)+0.84°
E)+)042°

Question 60

A newly isolated natural product was shown to be optically active.If a solution of 2.0 g in 10 mL of ethanol in a 50 cm tube gives a rotation of +2.57°,what is the specific rotation of this natural product?

Question 61

Which of the following is chiral?

A)cis-1-bromo-3-chlorocyclobutane
B)trans-1-bromo-3-chlorocyclobutane
C)cis-1,4-dimethylcyclohexane
D)cis-1,3-dimethylcyclohexane
E)trans-1,3-dimethylcyclohexane

Question 62

Draw the structure of (2S,3R)-dichloropentane.Take particular care to indicate three-dimensional stereochemistry detail properly.

Question 63

Provide a perspective drawing of the enantiomer of (2R,3S)-1,2,3-trichloropentane.

Question 64

Which of the following terms best describes the pair of compounds shown: enantiomers,diastereomers,or the same compound?

Question 65

What is the relationship between the following compounds?

A)superimposable without bond rotation
B)constitutional isomers
C)conformational isomers
D)diastereomers
E)enantiomers

Question 66

What is the relationship between the structures shown below?

A)enantiomers
B)diastereomers
C)configurational isomers
D)identical compounds
E)constitutional isomers

Question 67

Which of the following terms best describes the pair of compounds shown: enantiomers,diastereomers,or the same compound?

Question 68

Draw the structure of (2R,3S)-dichloropentane.Take particular care to indicate three-dimensional stereochemistry detail properly.

Question 69

Steroisomers which are not mirror image isomers are ________.

Question 70

Which of the following terms best describes the pair of compounds shown: enantiomers,diastereomers,or the same compound?

Question 71

Provide a perspective drawing of each diastereomer of (2R,3S)-1,2,3-trichloropentane.

Question 72

Which of the following terms best describes the pair of compounds shown: enantiomers,diastereomers,or the same compound?

Question 73

Provide a perspective drawing of (2R,3S)-1,2,3-trichloropentane.

Question 74

How many diastereomers exist for the compound below?

A)2
B)4
C)6
D)7
E)8

Question 75

What is the relationship between the following compounds?

A)enantiomers
B)diastereomers
C)constitutional isomers
D)conformational isomers
E)identical compounds

Question 76

Which of the following terms best describes the pair of compounds shown: enantiomers,diastereomers,or the same compound?

Question 77

Draw the stereoisomers of 1,3-dichlorocyclopentane.

Question 78

Which of the following terms best describes the pair of compounds shown: enantiomers,diastereomers,or the same compound?

Question 79

What is the relationship between the following compounds?

A)enantiomers
B)diastereomers
C)constitutional isomers
D)conformational isomers
E)identical compounds

Question 80

Draw the structure of any diastereomer of (2R,3S)-dichloropentane.Take particular care to indicate three-dimensional stereochemistry detail properly.