Question 1

What mass of (S)-(-)-mandelic acid is present in a 10 g sample which has an enantiomeric excess of 20% of the S-enantiomer?

Accepted Answer

The answer of What mass of (S)-(-)-mandelic acid is present...

Question 2

Which of the following structures represent the same stereoisomer?

Accepted Answer

A)  only 1 and 2 
B)  only 1 and 3 
C)  only 2 and 3 
D)  1, 2 and 3 
A)  only 1 and 2 
B)  only 1 and 3 
C)  only 2 and 3 
D)  1, 2 and 3

Question 3

Which of the following structures has a center of symmetry?

Accepted Answer

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

Question 4

Which of the following is a use of atropisomers?

Accepted Answer

A)  Used for the kinetic resolution of tertiary alcohols 
B)  Used for the kinetic resolution of secondary alcohols 
C)  Used for the kinetic resolution of primary alcohols 
D)  Used as a hydrogen bond catalyst in a single component domino reaction 
A)  Used for the kinetic resolution of tertiary alcohols 
B)  Used for the kinetic resolution of secondary alcohols 
C)  Used for the kinetic resolution of primary alcohols 
D)  Used as a hydrogen bond catalyst in a single component domino reaction

Question 5

Complete the following zig-zag structure so that it represents (2R,3S)-2,3-butanediol.

Accepted Answer

The answer of Complete the following zig-zag structure so that...

Question 6

Which of the following structures does not have a plane of symmetry?

Accepted Answer

A)  only 2 
B)  only 1 and 2 
C)  only 3 and 4 
D)  only 1, 2 and 4 
A)  only 2 
B)  only 1 and 2 
C)  only 3 and 4 
D)  only 1, 2 and 4

Question 7

How many stereoisomers of 4-bromo-2-pentanol, CH3CH(OH)CH2CHBrCH3, exist?

Accepted Answer

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

Question 8

Which of the following structures represent the same stereoisomer?

Accepted Answer

A)  only 1 and 2 
B)  only 1 and 3 
C)  only 2 and 3 
D)  1, 2 and 3 
A)  only 1 and 2 
B)  only 1 and 3 
C)  only 2 and 3 
D)  1, 2 and 3

Question 9

Complete the following zig-zag structure so that it represents (2R,3S)-3-chlorobutan-2-ol.

Accepted Answer

The answer of Complete the following zig-zag structure so that...

Question 10

Complete the following diagram so that it represents (S)-2-butanol.

Accepted Answer

The answer of Complete the following diagram so that it...

Question 11

Which of the following is the definition of a meso compound?

Accepted Answer

A)  A molecule with stereocenter centers which is chiral 
B)  A molecule with stereocenter centers which is not chiral 
C)  A diastereomer with no stereocenter centers 
D)  A chiral compound with more than one stereocenter center 
A)  A molecule with stereocenter centers which is chiral 
B)  A molecule with stereocenter centers which is not chiral 
C)  A diastereomer with no stereocenter centers 
D)  A chiral compound with more than one stereocenter center

Question 12

A pure sample of the R enantiomer of a compound has a specific rotation, [α], of −15°. A solution containing 0.6 g/mL of a mixture of enantiomers rotates plane polarized light by −3° in a 1 dm polarimeter. What is the enantiomeric excess (%ee) of the mixture?

Accepted Answer

A)  33% R 
B)  33% S 
C)  50% R 
D)  75% R 
A)  33% R 
B)  33% S 
C)  50% R 
D)  75% R

Question 13

What is the configuration of the two chiral centers in the following molecule?

Accepted Answer

A)  3R,5R 
B)  3R,5S 
C)  3S,5R 
D)  3S,5S 
A)  3R,5R 
B)  3R,5S 
C)  3S,5R 
D)  3S,5S

Question 14

How many isomers (constitutional and stereoisomers) exist for dimethylcyclobutane?

Accepted Answer

A)  3 
B)  4 
C)  5 
D)  6 
A)  3 
B)  4 
C)  5 
D)  6

Question 15

Which of the following statements is true?

Accepted Answer

A)  All mirror images are enantiomers 
B)  All molecules that have stereocenter centers are chiral 
C)  Isomers that are not superposable on their mirror images are enantiomers 
D)  Superposable structural isomers are enantiomers 
A)  All mirror images are enantiomers 
B)  All molecules that have stereocenter centers are chiral 
C)  Isomers that are not superposable on their mirror images are enantiomers 
D)  Superposable structural isomers are enantiomers

Exam 3: Stereoisomerism and Chirality

What mass of (S)-(-)-mandelic acid is present in a 10 g sample which has an enantiomeric excess of 20% of the S-enantiomer?

Which of the following structures represent the same stereoisomer?

Which of the following structures has a center of symmetry?

Which of the following is a use of atropisomers?

Complete the following zig-zag structure so that it represents (2R,3S)-2,3-butanediol.

Which of the following structures does not have a plane of symmetry?

How many stereoisomers of 4-bromo-2-pentanol, CH3CH(OH)CH2CHBrCH3, exist?

Which of the following structures represent the same stereoisomer?

Complete the following zig-zag structure so that it represents (2R,3S)-3-chlorobutan-2-ol.

Complete the following diagram so that it represents (S)-2-butanol.

Which of the following is the definition of a meso compound?

A pure sample of the R enantiomer of a compound has a specific rotation, [α], of −15°. A solution containing 0.6 g/mL of a mixture of enantiomers rotates plane polarized light by −3° in a 1 dm polarimeter. What is the enantiomeric excess (%ee) of the mixture?

What is the configuration of the two chiral centers in the following molecule?

How many isomers (constitutional and stereoisomers) exist for dimethylcyclobutane?

Which of the following statements is true?

Covalent Bonding and Shapes of Molecules

Alkanes and Cycloalkanes

Acids and Bases

Alkenes: Bonding, Nomenclature, and Properties

Reactions of Alkenes

Alkynes

Haloalkanes, Halogenation, and Radical Reactions

Nucleophilic Substitution and Beta-Elimination

Alcohols

Ethers, Epoxides, and Sulfides

Infrared Spectroscopy

Nuclear Magnetic Resonance Spectroscopy

Mass Spectrometry

An Introduction to Organometallic Compounds

Aldehydes and Ketones

Carboxylic Acids

Functional Derivatives of Carboxylic Acids

Enolate Anions and Enamines

Dienes, Conjugated Systems, and Pericyclic Reactions

Benzene and the Concept of Aromaticity

Reactions of Benzene and Its Derivatives

Amines

Catalytic Carbon-Carbon Bond Formation

Carbohydrates

Lipids

Amino Acids and Proteins

Nucleic Acids

Organic Polymer Chemistry

Filters

How many stereoisomers of 4-bromo-2-pentanol, CH₃CH(OH)CH₂CHBrCH₃, exist?