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 3E) A) and B)
F) A) and C)

Question 2

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

Accepted Answer

A)  3
B)  5
C)  6
D)  9E) A) and B)
F) None of the above

Question 3

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 enantiomersE) B) and C)
F) A) and D)

Question 4

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,5SE) A) and C)
F) All of the above

Question 5

A work glove is chiral but disposable surgical gloves are not.

Accepted Answer

A) True 
 B)False  True

Question 6

Of the following molecules, both 1 and 2 have a mirror plane of symmetry.

Accepted Answer

A) True 
 B)False

Question 7

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

Accepted Answer

A)  1
B)  2
C)  3
D)  4E) C) and D)
F) All of the above

Question 8

Which of the following structures is different from the other three?

Accepted Answer

A)  1
B)  2
C)  3
D)  4E) None of the above
F) All of the above

Question 9

Which of the following Newman projections represents meso-2,3-dibromobutane?

Accepted Answer

A)  1
B)  2
C)  3
D)  4E) All of the above
F) None of the above C

Question 10

A pure sample of the R enantiomer of a compound has a specific rotation, [\9\alpha\) ], of -5 ∘\circ∘ . A solution containing 0.6 g/mL of a mixture of enantiomers rotates plane polarized light by -3 ∘\circ∘ 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 E) A) and B)
F) C) and D)

Question 11

A natural product having [$\alpha$]D = +40.3$\circ$ has been isolated and purified. This indicates that the natural product is dextrorotatory.

Accepted Answer

A) True 
 B)False  True

Question 12

What is the correct order of the Cahn-Ingold-Prelog ranking of the following substituents as used in assigning R and S configurations of chiral centers? (higher ranking > lower ranking)  1.-CH2OH
2) -CHO
3) -OCH3
4) -OCOCH3

Accepted Answer

A)  3 > 4 > 1 > 2
B)  4 > 3 > 1 > 2
C)  3 > 4 > 2 > 1
D)  4 > 3 > 2 > 1E) B) and C)
F) A) and D)

Question 13

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 3E) None of the above
F) C) and D)

Question 14

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 4E) A) and B)
F) All of the above

Question 15

A solution containing 0.2 g/mL of a pure R enantiomer in a 1 dm polarimeter rotates plane polarized light by +3 ∘\circ∘ . What is the specific rotation of the R isomer?

Accepted Answer

A)  +0.6 ∘\circ∘ 
B)  +15 ∘\circ∘ 
C)  +67 ∘\circ∘ 
D)  +150 ∘\circ∘  E) A) and B)
F) None of the above

Question 16

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

Accepted Answer

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

Question 17

Complete the following diagram so that it represents (R)-2-bromobutane.

Accepted Answer

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

Question 18

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

Accepted Answer

A)  3
B)  5
C)  7
D)  9E) A) and B)
F) All of the above

Question 19

Which of the following statements is not true regarding pairs of enantiomers?

Accepted Answer

A)  They have identical melting points
B)  They have identical boiling points.
C)  They rotate plane polarized light in opposite directions
D)  They react at identical rates with chiral reagentsE) C) and D)
F) B) and D)

Question 20

A mixture containing 0.50 mmol of each enantiomer is called a ___________mixture.

Accepted Answer

The answer of A mixture containing 0.50 mmol of each...

Exam 3: Stereoisomerism and Chirality

Which of the following structures represent the same stereoisomer?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following statements is true?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A work glove is chiral but disposable surgical gloves are not.

Correct AnswerverifiedTrue

Of the following molecules, both 1 and 2 have a mirror plane of symmetry.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following structures is different from the other three?

Correct AnswerverifiedShow Answer

Which of the following Newman projections represents meso-2,3-dibromobutane?

Correct AnswerverifiedC

A pure sample of the R enantiomer of a compound has a specific rotation, [\9\alpha\) ], of -5 ∘\circ∘ . A solution containing 0.6 g/mL of a mixture of enantiomers rotates plane polarized light by -3 ∘\circ∘ in a 1 dm polarimeter. What is the enantiomeric excess (%ee) of the mixture?

Correct AnswerverifiedShow Answer

A natural product having [ α\alphaα ]D = +40.3 ∘\circ∘ has been isolated and purified. This indicates that the natural product is dextrorotatory.

Correct AnswerverifiedTrue

What is the correct order of the Cahn-Ingold-Prelog ranking of the following substituents as used in assigning R and S configurations of chiral centers? (higher ranking > lower ranking) 1.-CH2OH 2) -CHO 3) -OCH3 4) -OCOCH3

Correct AnswerverifiedShow Answer

Which of the following structures represent the same stereoisomer?

Correct AnswerverifiedShow Answer

Which of the following structures have a plane of symmetry?

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 +3 ∘\circ∘ . What is the specific rotation of the R isomer?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Complete the following diagram so that it represents (R)-2-bromobutane.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following statements is not true regarding pairs of enantiomers?

Correct AnswerverifiedShow Answer

A mixture containing 0.50 mmol of each enantiomer is called a ___________mixture.

Correct AnswerverifiedShow Answer

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True

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

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C

A pure sample of the R enantiomer of a compound has a specific rotation, [\9\alpha\) ], of -5^$\circ$. A solution containing 0.6 g/mL of a mixture of enantiomers rotates plane polarized light by -3^$\circ$in a 1 dm polarimeter. What is the enantiomeric excess (%ee) of the mixture?

Correct Answer
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A natural product having [ $\alpha$ ]_D = +40.3^$\circ$ has been isolated and purified. This indicates that the natural product is dextrorotatory.

Correct Answer
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True

What is the correct order of the Cahn-Ingold-Prelog ranking of the following substituents as used in assigning R and S configurations of chiral centers? (higher ranking > lower ranking) 1.-CH₂OH 2) -CHO 3) -OCH₃ 4) -OCOCH₃

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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 +3^$\circ$. What is the specific rotation of the R isomer?

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