Question 1

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 2

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 3

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

Accepted Answer

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

Question 4

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 5

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)  SevenE) B) and D)
F) All of the above

Question 6

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 7

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

Question 8

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

Accepted Answer

A)  3
B)  4
C)  5
D)  6E) B) and D)
F) A) and B)

Question 9

Which of the following structures has a center of symmetry?

Accepted Answer

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

Question 10

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.E) A) and B)
F) A) and C)

Question 11

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 12

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

Accepted Answer

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

Question 13

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 14

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∘  E) C) and D)
F) None of the above

Question 15

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 16

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 17

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?

Accepted Answer

A)  25% R
B)  40% S
C)  50% S
D)  70% R E) B) and C)
F) All of the above

Question 18

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...

Question 19

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

Accepted Answer

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

Question 20

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

Accepted Answer

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

Exam 3: Stereoisomerism and Chirality

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following structures represent the same stereoisomer?

Correct AnswerverifiedShow Answer

Which of the following structures has a center of symmetry?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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.

Correct Answerverifiedee = 25% o...View AnswerShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

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

Correct Answer
verified

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

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

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?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
ee = 25% o...
View Answer

Correct Answer
verified

Correct Answer
verified

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?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified