Deck 7: Isomerism 2: Chirality,enantiomers,and Diastereomers

Question 1

What is the relationship between the two following molecules?

A)They are enantiomers.
B)They are diastereomers.
C)They are conformational isomers.
D)They are unrelated.
E)They are the same molecule.

Answer 1

They are enantiomers.

Question 2

What is the relationship between the two following molecules?

A)They are enantiomers.
B)They are diastereomers.
C)They are conformational isomers.
D)They are unrelated.
E)They are the same molecule.

Answer 2

They are diastereomers.

Question 3

Which of the following is a diastereomer of the molecule below?

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

Answer 3

V

Question 4

Which of the following is chiral?

A)A sock
B)A spoon
C)An ear
D)A piece of string
E)A car tire

Question 5

Which structure (or structures)represents (or represent)the enantiomer of the molecule below?

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

Question 6

How many stereocenters are in the following molecule?

A)Zero
B)One
C)Two
D)Four
E)Eight

Question 7

Which of the following Fischer projections represent a pair of enantiomers?

A)I and II
B)III and IV
C)I and IV
D)II and III
E)None

Question 8

The Fischer projection shown below is a diastereomer of one or more of the Fischer projections labeled I-IV.Select the appropriate choice.

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

Question 9

Which choice is an enantiomer of the molecule below?

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

Question 10

What is the maximum number of stereoisomers possible for the following molecule?

A)Two
B)Three
C)Four
D)Six
E)Eight

Question 11

Which of the following compounds can be labeled as meso?

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

Question 12

Which of the following is achiral?

A)A helical seashell
B)A baseball glove
C)A pair of scissors
D)A pair of glasses
E)A shoe

Question 13

Which of the following has/have exactly two stereocenters?

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

Question 14

What is the maximum number of diastereomers possible for the following molecule?

A)One
B)Two
C)Three
D)Six
E)Eight

Question 15

What is the relationship between the two following molecules?

A)They are constitutional isomers.
B)They are conformational isomers.
C)They are diastereomers.
D)They are enantiomers.
E)They are the same molecule.

Question 16

Which of the following molecules is achiral?

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

Question 17

What is the relationship between the two following molecules?

A)They are constitutional isomers.
B)They are diastereomers.
C)They are conformational isomers.
D)They are enantiomers.
E)They are unrelated.

Question 18

Which of the following has a nonsuperimposable mirror image?

A)A baseball glove
B)A chair
C)A stapler
D)A DVD
E)A bell

Question 19

Which is the zigzag representation of the following Fischer projection?

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

Question 20

Which of the following compounds is not a meso compound?

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

Question 21

Which of the following has the same boiling point as the molecule below?

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

Question 22

What is the maximum possible number of stereoisomers for the following compound? Show your calculation.

Question 23

Which Fischer projection corresponds with the molecule below?

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

Question 24

Which of the following is considered an L sugar?

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

Question 25

Draw the mirror image of the following compound.

Question 26

A solution of a pure chiral molecule has a specific rotation of -23.1°.What is the specific rotation of a solution that is 83% (+)enantiomer and 17% (-)enantiomer?

A)23.1 $\degree$
B)66.0 $\degree$
C)15.0 $\degree$
D)-66.0 $\degree$
E)6.1 $\degree$

Question 27

Which Fischer structure corresponds with the molecule below?

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

Question 28

Draw a diastereomer for the molecule.

Question 29

A compound with a superimposable mirror image is called_______.

Question 30

What is the maximum possible number of stereoisomers for ibuprofen? Draw all of the possible stereoisomers.

Question 31

Which is the zigzag representation of the Fischer projection below?

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

Question 32

For the following molecule,label each stereocenter with an asterisk (*),and then draw all possible configurational isomers.

Question 33

Which alkene is most stable?

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

Question 34

Which alkene is least stable?

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

Question 35

For the following molecule,label each stereocenter with an asterisk (*),and then draw all possible configurational isomers.

Question 36

Suppose we dissolve 12.5 g of a chiral compound in 0.2 L of solution and place it in a tube that is 20.00 cm long.What is the sample's specific rotation if the observed rotation is experimentally determined to be 4 $\degree$ ?

A)20 $\degree$
B)12.5 $\degree$
C)0.125 $\degree$
D)8 $\degree$
E)32 $\degree$

Question 37

Two molecules that have the same connectivity and are nonsuperimposable mirror images of each other are called_______.

Question 38

Which set or sets of isomers could be separated using crystallization or column chromatography?

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

Question 39

If (+)ibuprofen has a specific rotation of +57 $\degree$ ,what is the specific rotation of (-)ibuprofen?

A)57 $\degree$
B)-57 $\degree$
C)26.5 $\degree$
D)0 $\degree$
E)Cannot be determined with the information given

Question 40

Draw the mirror image of the following compound.

Question 41

Draw the Fischer projection of the following structure.

Question 42

Draw an enantiomer and a diastereomer for the following molecule.

Question 43

What is the maximum possible number of diastereomers for the following molecule?

Question 44

Draw the zigzag representation for the following Fischer projection.

Question 45

Can the following two molecules be separated by column chromatography or recrystallization? Explain.

Question 46

Draw the Fischer projection of the following structure.

Question 47

For the following molecule,draw a stereoisomer that has physical and chemical properties different from those of the original molecule.

Question 48

Draw the zigzag representation for the following Fischer projection.

Question 49

A mixture of enantiomers contains 84% of the R enantiomer and 16% of the S enantiomer.What is the enantiomeric excess?

Question 50

Which of the following alkenes is more stable? Explain.

Question 51

Which of the following alkenes has the lower heat of combustion?

Question 52

A molecule that has at least two tetrahedral stereocenters but that is achiral overall is called a _______.

Question 53

Consider a mixture that is 80% (+)enantiomer and 20% (-)enantiomer.In which direction will the mixture rotate plane-polarized light? What is the enantiomeric excess (ee)of the mixture?

Question 54

Can the following two molecules be separated by column chromatography or recrystallization? Explain.

Question 55

Stereoisomers that are not mirror images of each other are called _______.

Question 56

Draw a stereoisomer that has the same boiling point as the molecule below.

Question 57

Can the following two molecules be separated by fractional distillation? Explain.

Question 58

A solution of a pure chiral molecule has a specific rotation of 17 $\degree$ .What is the specific rotation of a solution that is 80% (+)enantiomer and 20% (-)enantiomer?

Question 59

Draw an enantiomer and a diastereomer for the following molecule.Label which one is which.

Question 60

Why are cis alkenes less stable than trans alkenes?

Question 61

Suppose we dissolve 3 g of a chiral compound in 0.3 L of solution and place it in a tube that is 30.00 cm long.What is the sample's specific rotation if the observed rotation is experimentally determined to be 4.00 $\degree$ ?

Question 62

Draw the D stereoisomer of the following sugar.

Question 63

Is the following carbohydrate D or L? Explain how you know.