Deck 4: Stereochemistry

Question 1

What best describes the relationship between I and II shown below?

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

Answer 1

diastereomers

Question 2

What best describes the molecule shown below?

A)symmetrical and chiral
B)non-symmetrical and chiral
C)symmetrical and achiral
D)non-symmetrical and achiral

Answer 2

non-symmetrical and chiral

Question 3

Which of the following describes the three molecules shown below?

A)I and II are diastereomers.
B)I and III are enantiomers.
C)II and III are diastereomers.
D)I,II,and III are all diastereomers with each other.

Answer 3

I and II are diastereomers.

Question 4

How many chiral centres are there in 7-dehydrocholesterol (shown below)?

A)0
B)3
C)7
D)9

Question 5

How many stereoisomers does the following molecule contain?

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

Question 6

Which of the following (I,II,III)is an enantiomer of the molecule shown below?

A)only I
B)only II
C)both II and III
D)both I and II

Question 7

What best describes the absolute configuration of the epoxide shown below.

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

Question 8

What best describes the relationship between I and II shown below?

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

Question 9

What best describes the relationship between I and II shown below?

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

Question 10

What term refers to two molecules that differ at some but not all chiral centres?

A)enantiomers
B)diastereomers
C)constitutional isomers
D)atropisomers

Question 11

What best describes the molecule shown below?

A)symmetrical and chiral
B)non-symmetrical and chiral
C)symmetrical and achiral
D)non-symmetrical and achiral

Question 12

Which of the following describes the three molecules shown below?

A)I and II are enantiomers.
B)I and III are enantiomers.
C)II and III are enantiomers.
D)I,II,and III are not enantiomers with each other.

Question 13

Which of the following hexoses are distereomers with each other?

A)Glucose and mannose are diastereomers.
B)Glucose and galactose are diastereomers.
C)Galactose and mannose are diastereomers.
D)Glucose,mannose,and galactose are diastereomers with each other.

Question 14

What is the correct IUPAC name for the following compound?

A)(R,E)-4-bromo-3-methylpent-2-ene
B)(S,E)-4-bromo-3-methylpent-2-ene
C)(R,Z)-4-bromo-3-methylpent-2-ene
D)(S,Z)-4-bromo-3-methylpent-2-ene

Question 15

What best describes the relationship between I and II shown below?

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

Question 16

What is the absolute configuration of the molecule shown below?

A)2S,6S
B)2S,6R
C)2R,6S
D)2R,6R

Question 17

What can be said about L-Glyceraldehyde (shown below)?

A)It rotates plane-polarized light clockwise and has an absolute configuration of R.
B)It rotates plane-polarized light counter-clockwise and has an absolute configuration of R.
C)It rotates plane-polarized light clockwise and has an absolute configuration of S.
D)It rotates plane-polarized light counter-clockwise and has an absolute configuration of S.

Question 18

What is the absolute configuration around the chiral centre of the molecule shown below?

A)Choice R
B)Choice S
C)Choice E
D)Choice Z

Question 19

Which of the following (I,II,III)is the Fischer projection of the compound shown below?

A)only I
B)only II
C)both II and III
D)both I and III

Question 20

Which of the following best describes the stereochemical relationship between the hexoses shown below?

A)Glucose and mannose are enantiomers.
B)Glucose and galactose are enantiomers.
C)Galactose and mannose are enantiomers.
D)Glucose and mannose are diastereomers.

Question 21

What property to enantiomers differ by?

A)boiling point
B)optical rotation
C)polarity
D)solubility

Question 22

Figure 1
Figure 1: Epoxides I,II,III,IV
Which of the following compounds in Figure 1 is/are meso?

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

Question 23

Figure 1
Figure 1: Epoxides I,II,III,IV
Which of the following compounds in Figure 1 contains no chiral centres?

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

Question 24

What are the absolute configurations of the chiral centres in the molecule shown below?

A)1S,2R,4R
B)1S,2R,4S
C)1R,2S,4R
D)1R,2R,4S

Question 25

Which of the following best describes the stereochemical relationship of the structures shown below?

A)I and II are enantiomers,and III and IV are diastereomers.
B)I and IV are enantiomers,and II and III are diastereomers.
C)II and III are enantiomers,and I and IV are diastereomers.
D)I and IV are enantiomers,and II and III are meso.

Question 26

What is the relationship between the stereoisomers I,II,and III?

A)I is a meso compound;II and III are diastereomers.
B)II is a meso compound;I and III are enantiomers.
C)II is a meso compound;I and III are diastereomers.
D)III is a meso compound;I and II are enantiomers.

Question 27

How many stereoisomers does the following compound have?

A)2
B)3
C)4
D)8

Question 28

Figure 1
Figure 1: Epoxides I,II,III,IV
Which of the following epoxides in Figure 1 is/are achiral?

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

Question 29

What are the absolute configurations of the chiral centres in the molecule shown below?

A)2R,3E,5Z
B)2R,3Z,5E
C)2S,3E,5Z
D)2S,3Z,5E

Question 30

Which of the following compounds is optically active?

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

Question 31

What is the relationship between the two molecules shown below?

A)identical molecules
B)enantiomers
C)diastereomers
D)atropospmers

Question 32

Figure 1
Figure 1: Epoxides I,II,III,IV
Which of the following pairs in Figure 1 are enantiomers?

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

Question 33

Figure 1
Figure 1: Epoxides I,II,III,IV
In Figure 1,what is the absolute configuration of epoxide II?

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

Question 34

Which of the following compounds is considered meso?

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

Question 35

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

A)It rotates plane-polarized light clockwise and has an absolute configuration of R.
B)It rotates plane-polarized light counter-clockwise and has an absolute configuration of R.
C)It rotates plane-polarized light clockwise and has an absolute configuration of S.
D)It rotates plane polarized light counter-clockwise and has an absolute configuration of S.

Question 36

Which of the following molecules is achiral?

A)
B)
C)
D)

Question 37

Figure 1
Figure 1: Epoxides I,II,III,IV
Which of the following epoxides in Figure 1 is/are optically active?

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

Question 38

What is the ratio of stereoisomers in a mixture that contains an enantiomeric excess of 20% R stereoisomer isomer?

A)20% R,80% S
B)40% R,60% S
C)60% R,40% S
D)80% R,20% S

Question 39

If a sample contains 70% of the (+)isomer and 30% of the (-)isomer,what is its enantiomeric excess?

A)70% (+)
B)40% (+)
C)30% (+)
D)30% (-)

Question 40

Figure 1
Figure 1: Epoxides I,II,III,IV
In Figure 1,what is the absolute configuration of epoxide III?

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

Question 41

Optical purity is used to determine enantiomeric excess.

Question 42

Only carbon can be a chiral centre.

Question 43

Z stereochemistry represents the highest-priority groups being on the same side of an alkene.

Question 44

Meso compounds contain an internal plane of symmetry.

Question 45

Any molecule that has a non-superimposable mirror image is considered chiral.

Question 46

According to the Cahn Ingold Prelog rules,isotopes are not considered when assigning substituent priority.

Question 47

Two molecules that differ at some but not all chiral centres are referred to as diastereomers.

Question 48

If the penultimate carbon of a carbohydrate has the hydroxyl group pointing right,it is considered a D sugar.

Question 49

2-bromo-3-methylbutane has four stereoisomers.

Question 50

Diastereomers have identical physical properties.

Question 51

Molecules that rotate plane-polarized light counter-clockwise are denoted as L.

Question 52

Any compound that has a chiral centre is considered a chiral molecule.

Question 53

R absolute configuration represents a counter-clockwise arrangement of the highest-priority substituents.

Question 54

In a Fischer projection,the horizontal bonds are assumed to go into the page.

Question 55

Molecules that rotate plane-polarized light clockwise have an absolute configuration of R.

Question 56

A molecule that contains an internal mirror plane is considered meso and achiral.

Question 57

A molecule is chiral if it possesses a superimposable mirror image.

Question 58

According to the Cahn-Ingold-Prelog rules,lone pairs electrons have a lower priority than a hydrogen atom.

Question 59

2-bromo-3-methylbutane has two chiral centres.

Question 60

Specific rotation takes the concentration of a sample into account.

Question 61

E and Z are types of stereochemistry.

Question 62

Determine the stereochemical relationship of II with each of the other seven molecules.(Enantiomers,Diastereomers,Identical molecules)

Question 63

Identify the absolute configuration of the chiral centres in the following compound.

Question 64

A 50:50 sample of enantiomers is also known as a _______________ mixture.

Question 65

A molecule with chiral centres and an internal plane of symmetry is considered _______________.

Question 66

Bonds that go into the page are represented in the _______________ direction on a Fischer projection.

Question 67

A _______________ is when molecules are drawn in two dimensions in a cross-like format

Question 68

If the highest-priority substituents are on opposite sides of an alkene,it is designated with the Z configuration.

Question 69

Draw glucose in the zig-zag template shown below,given the Fischer projection.

Question 70

Enantiomers have _______________ physical properties.

Question 71

Stereoisomers that are a result of hindered rotation are referred to as _______________ .

Question 72

Stereoisomers that differ at some but not all chiral centres are referred to as _______________.

Question 73

A racemic mixture of 2-butanol can have a different boiling point than its individual enantiomers.

Question 74

The maximum number of stereoisomers a compound can have is _______________ where n is the number of chiral centres.

Question 75

Determine the absolute configuration of the chiral centres in the molecule shown below.

Question 76

Stereoisomers are a type of constitutional isomer.

Question 77

Stereoisomers that differ at all chiral centres are referred to as _______________ .

Question 78

A molecule name preceded by (+)rotates plane-polarized light _______________ .

Question 79

Meso compounds increase the number of possible stereoisomers.

Question 80

Convert the chair structure I into a line structure,and determine its stereochemical relationship to II shown below.