Question 1

A solution containing 0.04 g/mL of a pure S enantiomer in a 1 dm polarimeter rotates plane polarized light by +2 °\degree° . What is the specific rotation of the R isomer?

Accepted Answer

A)   -50 °\degree° 
B)   -20 °\degree° 
C)   +10 °\degree° 
D)   +50 °\degree°

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.

Question 3

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 4

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

Accepted Answer

A)   3
B)   5
C)   7
D)   9

Question 5

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

Accepted Answer

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

Question 6

How many stereoisomers of 2,3-butanediol, CH3CH(OH) CH(OH) CH3, exist?

Accepted Answer

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

Question 7

Which of the following structures has a center of symmetry?

Accepted Answer

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

Question 8

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 9

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

Accepted Answer

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

Question 10

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

Question 11

Which of the following structures is chiral?

Accepted Answer

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

Question 12

A pure sample of the R enantiomer of a compound has a specific rotation, [a], of +20 °\degree° . A solution containing 0.2 g/mL of a mixture of enantiomers rotates plane polarized light by -2 °\degree°  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

Question 13

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

Accepted Answer

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

Question 14

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

Accepted Answer

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

Question 15

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

Accepted Answer

A)   2
B)   3
C)   4
D)   5

Question 16

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

Accepted Answer

A)   3
B)   5
C)   6
D)   9

Question 17

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

Accepted Answer

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

Question 18

A solution containing 0.2 g/mL of a pure R enantiomer in a 1 dm polarimeter rotates plane polarized light by +2.8 °\degree° . What is the rotation of a solution containing 0.4 g/mL of the R isomer in the same polarimeter?

Accepted Answer

A)   +0.7 °\degree° 
B)   +1.4 °\degree° 
C)   +2.8 °\degree° 
D)   +5.6 °\degree°

Question 19

How many stereoisomers of 3-bromo-2-butanol, CH3CH(OH) CHBrCH3, exist?

Accepted Answer

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

Question 20

Which of the following structures have a plane of symmetry?

Accepted Answer

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

Exam 3: Stereoisomerism and Chirality

Which of the following structures has a center of symmetry?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

How many stereoisomers of 2,3-butanediol, CH3CH(OH) CH(OH) CH3, exist?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

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

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

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Which of the following structures is chiral?

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A solution containing 0.04 g/mL of a pure S enantiomer in a 1 dm polarimeter rotates plane polarized light by +2 °\degree° . What is the specific rotation of the R isomer?

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

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

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

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How many stereoisomers of 3-bromo-2-butanol, CH3CH(OH) CHBrCH3, exist?

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

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Which of the following structures have a plane of symmetry?

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

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A solution containing 0.2 g/mL of a pure R enantiomer in a 1 dm polarimeter rotates plane polarized light by +2.8 °\degree° . What is the rotation of a solution containing 0.4 g/mL of the R isomer in the same polarimeter?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct Answer
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How many stereoisomers of 2,3-butanediol, CH₃CH(OH) CH(OH) CH₃, exist?

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

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A solution containing 0.04 g/mL of a pure S enantiomer in a 1 dm polarimeter rotates plane polarized light by +2 $\degree$ . What is the specific rotation of the R isomer?

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How many stereoisomers of 3-bromo-2-butanol, CH₃CH(OH) CHBrCH₃, exist?

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A solution containing 0.2 g/mL of a pure R enantiomer in a 1 dm polarimeter rotates plane polarized light by +2.8 $\degree$ . What is the rotation of a solution containing 0.4 g/mL of the R isomer in the same polarimeter?

Correct Answer
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Correct Answer
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