Complete Test Bank The Three-Dimensional Shape of Ch15

General, Organic and Biological Chemistry, 4e (Smith)

Chapter 15 The Three-Dimensional Shape of Molecules

1) Which object is chiral?

A) A sock

B) A shoe

C) A baseball

D) A fork

E) More than one of the objects is chiral.

2) How can the following molecules be classified correctly?

A) II and III are identical molecules

B) I and II are constitutional isomers

C) I and III are stereoisomers

D) II and III are stereoisomers

E) Both statements B and D are correct

3) Which molecule is chiral?

A)

B)

C)

D)

4) Which molecule is chiral?

A)

B)

C)

D)

5) How many chirality centers does the following molecule contain?

A) 0

B) 1

C) 2

D) 3

6) How many chirality centers does the following molecule contain?

A) 0

B) 1

C) 2

D) 3

7) How many chirality centers does the following molecule contain?

A) 1

B) 2

C) 3

D) 8

8) Which molecule is not an enantiomer of the molecule whose structure is shown below?

A)

B)

C)

D) All the molecules are enantiomers of the original structure.

9) Which, if any, of the labeled carbon atoms in the compound below is a chirality center?

A) C1 is the only chirality center.

B) C2 is the only chirality center.

C) Both C1 and C2 are chirality centers.

D) Neither C1 nor C2 are chirality centers.

10) Which, if any, of the labeled carbon atoms in the compound below is a chirality center?

A) C1 is the only chirality center.

B) C2 is the only chirality center.

C) Both C1 and C2 are chirality centers.

D) Neither C1 nor C2 are chirality centers.

11) Which, if any, of the labeled carbon atoms in the compound below is a chirality center?

A) C2 is the only chirality center.

B) C2, C3, and C4 and all chirality centers.

C) C3 and C4 are both chirality centers

D) C2 and C4 and both chirality centers

E) C1 and C3 are both chirality centers

12) Which molecule is chiral?

A) 1-pentanol

B) cyclopentanol

C) 2-methylcyclopentanol

D) 2-methylpentane

E) More than one of the molecules is chiral.

13) How many chirality centers are present in the compound below?

A) 0

B) 1

C) 2

D) 3

E) 5

14) Which choice is the enantiomer of the molecule given below?

A)

B)

C)

D) None of these molecules is an enantiomer of the original molecule.

15) Which choice is not one of the properties that are identical for two enantiomers of the same compound?

A) Melting point

B) Interaction with plane-polarized light

C) Boiling point

D) Solubility

E) None of the choices are correct.

16) A compound that does not change the direction of plane-polarized light is called

A) Chiral

B) Diastereomer

C) Achiral

D) Neutral

E) Acidic

17) Two enantiomers rotate plane-polarized light ________.

A) to an equal extent but in opposite directions

B) to an equal extent in the same direction

C) to vastly differing extents in random directions

D) exactly 90º clockwise

18) Which molecule is an enantiomer of the one shown below?

A)

B)

C)

D) None of the molecules is an enantiomer of the original molecule.

19) Diastereomers are stereoisomers that are ________.

A) mirror images of each other

B) not mirror images of each other

C) nonsuperimposable mirror images of each other

D) superimposable on each other

20) The Fischer projection formula for D-mannose, a hexose sugar, is shown below. How many chirality centers are in D-mannose?

A) 2

B) 4

C) 5

D) 6

21) The Fischer projection for threose, a tetrose sugar, is shown below. How many chirality centers are in threose?

A) 1

B) 3

C) 2

D) 4

22) Which choice shows the given molecule correctly represented as a Fischer projection?

A)

B)

C)

D)

23) Consider the stereoisomers (A–E) drawn below:

Which structure is an enantiomer of structure A?

A) Structure B

B) Structure C

C) Structure D

D) Structure E

24) Consider the stereoisomers (A–E) drawn below:

Structures A and C are related as ________.

A) identical molecules

B) enantiomers

C) constitutional isomers

D) diastereomers

25) Consider the stereoisomers (A–E) drawn below:

Which structure(s) is/are a diastereomer of structure C?

A) Structure A

B) Structure B

C) Structure D

D) Structure E

E) None of the structures is a diastereomer of structure C.

26) Consider the stereoisomers (A–E) drawn below:

Which structure(s) is/are diastereomers of structure E?

A) Structure A

B) Structure B

C) Structure C

D) Structure D

E) Structures A and B

27) Consider the stereoisomers (A–E) drawn below:

Structures C and D are ________.

A) identical molecules

B) enantiomers

C) constitutional isomers

D) diastereomers

28) Enantiomers are stereoisomers that are ________.

A) mirror images of each other that are identical

B) not mirror images of each other

C) nonsuperimposable mirror images of each other

D) cis–trans isomers of each other

29) In a Fischer projection, ________.

A) horizontal lines represent bonds that come out of the plane on wedges, and the vertical lines represent bonds that go back on dashed lines

B) vertical lines represent bonds that come out of the plane on wedges, and the horizontal lines represent bonds that go back on dashed lines

C) horizontal lines represent bonds that are in the plane of the paper, and the vertical lines represent bonds that go back on dashed lines

D) vertical lines represent bonds that are in the plane of the paper, and the horizontal lines represent bonds that go back on dashed lines

30) How are the Fischer projections below related?

A) Identical molecules

B) Enantiomers

C) Constitutional isomers

D) Diastereomers

31) Penicillamine is used to treat arthritis. How many chirality centers are present in penicillamine?

A) 0

B) 1

C) 2

D) 3

E) More than 3

32) How many chirality centers are present in the following molecule?

A) 0

B) 1

C) 2

D) 3

E) More than 3

33) Which compound has the most stereoisomers?

A)

B)

C)

D)

E)

34) Which is NOT another name for a chirality center?

A) Stereogenic center

B) Chiral carbon

C) Asymmetric carbon

D) Tetravalent carbon

35) Which statement is not true?

A) A molecule that is not superimposable on its mirror image is a chiral molecule.

B) Enantiomers are mirror images that are not superimposable.

C) A carbon atom surrounded by four different groups is a chirality center.

D) A racemic mixture contains an equal mixture of two diastereomers.

36) Which statement is true?

A) A carbon that is part of a multiple bond is always a chirality center.

B) The carbon atom in a CH2 group is a chirality center only when it is part of a ring.

C) Stereoisomers always have the same functional groups.

D) Diastereomers are mirror image isomers that are not superimposable.

37) The drug Thalidomide was ________.

A) invented by Frances Oldham Kelsey

B) sold as a mixture of its two enantiomers, and each of these stereoisomers has a different biological activity

C) was approved for use in the United States

D) All of the choices are correct.

38) Which nonsteroidal anti-inflammatory drug(s) (NSAID) is/are sold as a racemic mixture?

A) Naproxen

B) Ibuprofen

C) Both Naproxen and Ibuprofen are sold as a racemic mixture.

D) Neither Naproxen nor Ibuprofen are sold as a racemic mixture.

39) The drug L-Dopa ________.

A) is marketed as a racemic mixture for the treatment of Parkinson's disease

B) was first isolated from the leaves of the broad bean Vicia faba

C) is a chiral molecule with two chirality centers

D) has only one enantiomer that is active against Parkinson's disease

40) How many enantiomers can a chiral stereoisomer have?

A) 0

B) 1

C) 2

D) The number of enantiomers depends on the number of chirality centers.

41) How many diastereomers can a chiral stereoisomer have?

A) 1

B) 2

C) 3

D) The number of diastereomers depends on the number of chirality centers.

42) Which structure represents the three-dimensional structure of the Fischer projection shown?

A)

B)

C)

D)

43) Alanine, shown below, is a naturally occurring chiral amino acid. Which pair represents the two enantiomers of alanine?

A)

B)

C)

44) Which statement concerning stereochemistry is incorrect?

A) An object or molecule is chiral if it is nonsuperimposable on its mirror image.

B) A chiral molecule is optically active and rotates plane polarized light either clockwise or counterclockwise.

C) Enantiomers are superimposable mirror image isomers.

D) Diastereomers are stereoisomers that are not related as mirror images.

45) The specific rotation of pure cholesterol was measured to be -32. Based on this information, which statement concerning cholesterol is NOT true?

A) Cholesterol is a chiral compound.

B) Cholesterol is optically inactive.

C) Cholesterol is levorotatory.

D) Cholesterol rotates plane polarized light in a counterclockwise direction.

46) Carbohydrates, lipids, proteins, and nucleic acids are all chiral biomolecules. What does the term chiral indicate about a molecule?

A) The molecule can be synthesized by the body.

B) The molecule can be digested by the body.

C) The molecule has a mirror image.

D) The molecule and its mirror image are not identical.

47) Which property of enantiomers is not identical?

A) Melting point

B) Boiling point

C) Solubility

D) Specific rotation

E) All of these properties are identical for a pair of enantiomers.

48) Propranol, shown below, is a chiral compound that exists as a pair of enantiomers. One enantiomer is used to treat irregular heartbeats, and the other enantiomer is used as a contraceptive. Identify the chirality center(s) in Propranol.

A) C1

B) C2

C) C3

D) C4

E) C1 and C3

49) Carvone, shown below, is a chiral compound that exists as a pair of enantiomers. One enantiomer has the odor of caraway, and the other enantiomer has the odor of spearmint.  Identify the chirality center(s) in carvone.

A) C1

B) C2

C) C3

D) C4

E) C1 and C3

50) Enantiomers are mirror images that are not superimposable.

51) Another term in common use for a chirality center is an asymmetric carbon.

52) Any molecule with one chirality center is a chiral compound.

53) Any molecule with two chirality centers is an achiral compound.

54) Two enantiomers typically have the same biological activity.

55) Recent rulings by the Food and Drug Administration have encouraged the development of so-called racemic switches, the patenting and marketing of a single enantiomer that was originally sold as a racemic mixture.

56) The amino acid alanine found in the proteins of the body has a melting point of 297 °C and a specific rotation of +8.5. The enantiomer of alanine would have a melting point of –297 °C and a specific rotation of –8.5.

57) The Fischer projection shown on the right properly represents the three-dimensional compound shown on the left.

58) The Fischer projection shown on the right properly represents the ball and stick model of the compound shown on the left.

59) Hexane (CH3CH2CH2CH2CH2CH3) has a mirror image, but it does not have an enantiomer.

60) The molecule below is achiral.

61) A carbonyl carbon is a common example of a chirality center.

62) cis-2-butene and trans-2-butene are enantiomers.

63) The compound 3,6-diethyl-6-methyl-3-decanethiol is a chiral molecule with more than one chirality center.

64) The compound 4-methyl-2-hexene is not a chiral molecule.

65) For an odor to be perceived, a molecule must bind to an olfactory receptor, resulting in a nerve impulse that travels to the brain.

66) A nail is an example of a chiral object.

67) There are six chirality centers in the simple sugar D-glucose, shown below.

68) Enantiomers may have different odors because they bind with chiral receptors and each enantiomer fits the chiral receptors in a different way.

69) The Fischer projection shown to the right represents the enantiomer of the three-dimensional structure to the left.

70) A chiral molecule has at least one carbon atom that has four different substituents bonded to it.

71) The compound 3-methylcyclopentanol contains one chirality center.

72) In organic molecules, oxygen atoms cannot be chirality centers.

73) A human foot is a chiral object.

74) The alkyl bromide below contains one chirality center.

75) If a stereoisomer has an enantiomer, it does not have a diastereomer.

76) All tertiary alcohols (3°) are chiral.

77) The major product of the dehydration of the alcohol below has one chirality center.

78) Aspartame contains two chirality centers.

79) The dipeptide molecule shown below contains two chirality centers.

80) The Fischer projection to the right represents the compound to the left.

81) Only chiral molecules have a mirror image.

82) Two enantiomers rotate plane-polarized light to an equal extent but in opposite directions.

83) If one enantiomer causes plane-polarized light to rotate clockwise, that enantiomer is called dextrorotatory.

84) If one enantiomer causes plane-polarized light to rotate counterclockwise, that enantiomer is labeled as the (–)-enantiomer.

85) A sample tube containing equal amounts of two enantiomers would be optically inactive.

86) A compound with one chirality center exists as a pair of enantiomers.

87) cis-2-Butene and trans-2-butene are stereoisomers related as diastereomers.

88) The cis and trans isomers of an alkene represent one example of stereoisomers.

89) All molecules that have carbons with a tetrahedral shape are chiral.

90) A carbon atom bonded to four different groups is called a/an ________.

91) A sample containing an equal amount of two enantiomers is called a/an ________ mixture.

92) A compound with two chirality centers has a maximum of ________ possible stereoisomers.

93) A compound with three chirality centers has a maximum of ________ possible stereoisomers.

94) ________ are stereoisomers that are not mirror images of each other.

95) Ethambutol (structure shown) is a bacteriostatic antimycobacterial drug prescribed to treat tuberculosis (Mycobacterium tuberculosis). There are ________ chirality centers in ethambutol.

96) Ethambutol (structure shown) is a bacteriostatic antimycobacterial drug prescribed to treat tuberculosis (Mycobacterium tuberculosis). There are ________ chirality centers in ethambutol.

97) Ampicillin (structure shown) is an antibiotic that has been used extensively to treat bacterial infections since 1961. There are ________ chirality centers in ampicillin.

98) Benazepril (structure shown) is a medication that has been used to treat high blood pressure. There are ________ chirality centers in benzaepril.

99) The shape of a chirality center is ________.

100) cis-2-Hexene and trans-3-hexene are ________ isomers.

101) Chiral compounds rotate plane polarized light. A compound with the ability to rotate plane polarized light is referred to as being ________.