Question 1

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 2

Which of the following statements regarding optical rotation is not true?

Accepted Answer

A) All (+) enantiomers are dextrorotatory. 
B) All R enantiomers are dextrorotatory. 
C) All (-) enantiomers rotate plane-polarized light in a counterclockwise direction. 
D) All (+) and (-) enantiomers rotate plane-polarized light in opposite directions. 
A) All (+) enantiomers are dextrorotatory. 
B) All R enantiomers are dextrorotatory. 
C) All (-) enantiomers rotate plane-polarized light in a counterclockwise direction. 
D) All (+) and (-) enantiomers rotate plane-polarized light in opposite directions.

Question 3

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 4

How many stereoisomers of 2,4-pentanediol, CH3CH(OH)CH2CH(OH)CH3, exist?

Accepted Answer

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

Question 5

Complete the following Newman projection so that it represents (2S,3S)-2,3-butanediol.

Accepted Answer

The answer of Complete the following Newman projection so that...

Question 6

What mass of (S)-(-)-mandelic acid is present in a 10 g sample which has an enantiomeric excess of 30% of the S-enantiomer?

Accepted Answer

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

Question 7

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 8

The specific rotation of the S-enantiomer of a compound is -120º. What is the enantiomeric excess of a sample of the compound that has a measured specific rotation of -30º.

Accepted Answer

ee = 25% o

Question 9

The terms that best describe the relationship between (2R,3S)-2,3-butanediol and (2S,3S)-2,3-butanediol are configurational and diastereomers.

Accepted Answer

A) True 
 B)False

Question 10

A solution of 0.1 g/mL of a pure R enantiomer in a 1 dm polarimeter rotates plane polarized light by +4.8$\circ$. What is the rotation observed on this solution in a 2 dm polarimeter?

Accepted Answer

A) +2.4$\circ$ 
B) +4.8$\circ$ 
C) +9.6$\circ$ 
D) +19.2$\circ$ 
A) +2.4$\circ$ 
B) +4.8$\circ$ 
C) +9.6$\circ$ 
D) +19.2$\circ$

Question 11

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 12

Which of the following structures has a center of symmetry (i.e., center of inversion)?

Accepted Answer

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

Question 13

How many stereoisomers of 2,3-dimethylbutane, (CH3)2CHCH(CH3)2, exist?

Accepted Answer

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

Question 14

How many chiral centers are there in the following molecule (the naturally occurring stereoisomer is the male hormone testosterone)?

Accepted Answer

A) Three 
B) Four 
C) Six 
D) Seven 
A) Three 
B) Four 
C) Six 
D) Seven

Question 15

A pure sample of the R enantiomer of a compound has a specific rotation, [$\alpha$], of +20$\circ$. A solution containing 0.2 g/mL of a mixture of enantiomers rotates plane polarized light by -2$\circ$ in a 1 dm polarimeter. What is the enantiomeric excess (%ee) of the mixture?

Accepted Answer

A) 25% R 
B) 40% S 
C) 50% S 
D) 70% R 
A) 25% R 
B) 40% S 
C) 50% S 
D) 70% R

Question 16

Complete the following Fischer diagram so that it represents (2R,3R)-3-bromobutan-2-ol.

Accepted Answer

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

Question 17

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

Accepted Answer

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

Question 18

The number of chiral centers in progesterone (shown below) is ______.

Accepted Answer

The answer of The number of chiral centers in progesterone...

Question 19

Complete the following Fischer diagram so that it represents (2R,3R)-butane-2,3-diol.

Accepted Answer

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

Question 20

Complete the following Fischer diagram so that it represents (2R,3S)-3-bromobutan-2-ol.

Accepted Answer

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

Exam 3: Stereoisomerism and Chirality

Which of the following structures represent the same stereoisomer?

Which of the following statements regarding optical rotation is not true?

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

How many stereoisomers of 2,4-pentanediol, CH3CH(OH)CH2CH(OH)CH3, exist?

Complete the following Newman projection so that it represents (2S,3S)-2,3-butanediol.

What mass of (S)-(-)-mandelic acid is present in a 10 g sample which has an enantiomeric excess of 30% of the S-enantiomer?

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

The specific rotation of the S-enantiomer of a compound is -120º. What is the enantiomeric excess of a sample of the compound that has a measured specific rotation of -30º.

The terms that best describe the relationship between (2R,3S)-2,3-butanediol and (2S,3S)-2,3-butanediol are configurational and diastereomers.

A solution of 0.1 g/mL of a pure R enantiomer in a 1 dm polarimeter rotates plane polarized light by +4.8 ∘\circ∘ . What is the rotation observed on this solution in a 2 dm polarimeter?

Which of the following structures has a center of symmetry?

Which of the following structures has a center of symmetry (i.e., center of inversion)?

How many stereoisomers of 2,3-dimethylbutane, (CH3)2CHCH(CH3)2, exist?

How many chiral centers are there in the following molecule (the naturally occurring stereoisomer is the male hormone testosterone)?

A pure sample of the R enantiomer of a compound has a specific rotation, [ α\alphaα ], of +20 ∘\circ∘ . A solution containing 0.2 g/mL of a mixture of enantiomers rotates plane polarized light by -2 ∘\circ∘ in a 1 dm polarimeter. What is the enantiomeric excess (%ee) of the mixture?

Complete the following Fischer diagram so that it represents (2R,3R)-3-bromobutan-2-ol.

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

The number of chiral centers in progesterone (shown below) is ______.

Complete the following Fischer diagram so that it represents (2R,3R)-butane-2,3-diol.

Complete the following Fischer diagram so that it represents (2R,3S)-3-bromobutan-2-ol.

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 2,4-pentanediol, CH₃CH(OH)CH₂CH(OH)CH₃, exist?

A solution of 0.1 g/mL of a pure R enantiomer in a 1 dm polarimeter rotates plane polarized light by +4.8^$\circ$. What is the rotation observed on this solution in a 2 dm polarimeter?

How many stereoisomers of 2,3-dimethylbutane, (CH₃)₂CHCH(CH₃)₂, exist?

A pure sample of the R enantiomer of a compound has a specific rotation, [ $\alpha$ ], of +20^$\circ$. A solution containing 0.2 g/mL of a mixture of enantiomers rotates plane polarized light by -2^$\circ$ in a 1 dm polarimeter. What is the enantiomeric excess (%ee) of the mixture?