Question 1

A pure sample of the R enantiomer of a compound has a specific rotation, [a], of -15 °\degree° . A solution containing 0.6 g/mL of a mixture of enantiomers rotates plane polarized light by -3 °\degree°  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) None of the above
F) A) and C)

Question 2

The specific rotation of the S-enantiomer of a compound is -120$\degree$. A student determines that a sample of the compound has a specific rotation of +60$\degree$. What mass of the S-enantiomer is present in 10 g of the sample

Accepted Answer

The answer of The specific rotation of the S-enantiomer of...

Question 3

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 4

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 5

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

Accepted Answer

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

Question 6

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)   lower ranking)    A)  3 > 4 > 1 > 2 B)  4 > 3 > 1 > 2 C)  3 > 4 > 2 > 1 D)  4 > 3 > 2 > 1" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

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

Question 7

Which of the following have the R configuration?

Accepted Answer

A)   only 1
B)   only 2
C)   only 1 and 2
D)   1, 2 and 3E) None of the above
F) B) and C)

Question 8

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) None of the above

Question 9

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 10

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 11

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) C) and D)
F) A) and C)

Question 12

How much of the R enantiomer is present in 10 g of a mixture which has an enantiomeric excess of 20% of the S isomer?

Accepted Answer

A)   1 g
B)   2 g
C)   4 g
D)   6 gE) None of the above
F) A) and B)

Question 13

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) All of the above
F) B) and C)

Question 14

How many stereoisomers of 2,4-dimethylpentane, (CH3) 2CHCH2CH(CH3) 2, exist?

Accepted Answer

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

Question 15

Which of the following substituents has the highest priority according to the Cahn-Ingold-Prelog system used in assigning R and S configurations?

Accepted Answer

A)   -COOH
B)   -CHO
C)   -CH2OH
D)   -CH3E) B) and C)
F) A) and D)

Question 16

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

Accepted Answer

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

Question 17

Which of the following is the definition of a pair of diastereomers?

Accepted Answer

A)   A pair of structures that are superposable mirror images of one another
B)   A pair of stereoisomers that are non-superposable mirror images of one another
C)   A pair of stereoisomers that are not mirror images of one another
D)   A pair of stereoisomers that have equal specific rotationsE) A) and B)
F) A) and C) C

Question 18

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

Accepted Answer

A)   +0.6 °\degree° 
B)   +15 °\degree° 
C)   +67 °\degree° 
D)   +150 °\degree°E) A) and B)
F) A) and C)

Question 19

How many stereoisomers of 3-chloro-2-methylbutane, (CH3) 2CHCHClCH3, exist?

Accepted Answer

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

Question 20

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 C)
F) B) and D)

Exam 3: Stereoisomerism and Chirality

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

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The specific rotation of the S-enantiomer of a compound is -120 °\degree° . A student determines that a sample of the compound has a specific rotation of +60 °\degree° . What mass of the S-enantiomer is present in 10 g of the sample

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

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

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

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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)

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Which of the following have the R configuration?

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

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

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

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

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How much of the R enantiomer is present in 10 g of a mixture which has an enantiomeric excess of 20% of the S isomer?

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Which of the following statements is true?

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How many stereoisomers of 2,4-dimethylpentane, (CH3) 2CHCH2CH(CH3) 2, exist?

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Which of the following substituents has the highest priority according to the Cahn-Ingold-Prelog system used in assigning R and S configurations?

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

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Which of the following is the definition of a pair of diastereomers?

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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 °\degree° . What is the specific rotation of the R isomer?

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How many stereoisomers of 3-chloro-2-methylbutane, (CH3) 2CHCHClCH3, exist?

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Which of the following structures represent the same stereoisomer?

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

Correct Answer
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The specific rotation of the S-enantiomer of a compound is -120 $\degree$ . A student determines that a sample of the compound has a specific rotation of +60 $\degree$ . What mass of the S-enantiomer is present in 10 g of the sample

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How many stereoisomers of 2,4-dimethylpentane, (CH₃) ₂CHCH₂CH(CH₃) ₂, 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 +3 $\degree$ . What is the specific rotation of the R isomer?

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How many stereoisomers of 3-chloro-2-methylbutane, (CH₃) ₂CHCHClCH₃, exist?

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