Stereochemistry
Quiz #4
Question
The molecules above are (Z) configurations.
True (A) False (B)
Question
Indicate the relationship of the pair of molecules shown.
A. same molecules
B. mirror images
C. different molecules
D. constitutional isomers
E. cis and trans isomers
Question
Consider the molecule below. What is the maximum number of methyl
groups that can be in the equatorial position at the same time?
A. 0
B. 1
C. 2
D. 3
E. 4
Question
Both cis- and trans-1,2-dimethylcyclohexane are chiral.
True (A) False (B)
Question
How many of the following compounds contain an
internal mirror plane of symmetry?
A) 1
B) 2
C) 3
D) 4
Question
Which of the following molecules is chiral?
B
A
C
D
Question
What is the stereochemical designation of
the following molecule?
A. (R)
B. (S)
C. non-chiral (achiral)
Question
Indicate the relationship of the pair of molecules shown.
A. same molecules
B. enantiomers
C. diastereomers
D. different molecules
E. constitutional isomers
Question
Indicate the relationship of the pair of molecules
shown.
A. same molecules
B. enantiomers
C. diastereomers
D. different molecules
E. constitutional isomers
Question
Indicate the relationship of the pair of
molecules shown.
A. same molecules
B. enantiomers
C. diastereomers
D. different molecules
E. constitutional isomers
Question
Indicate the relationship of the pair of
molecules shown.
A. same molecules
B. enantiomers
C. diastereomers
D. different molecules
E. constitutional isomers
Question
Indicate the relationship of the pair of
molecules shown.
A. same molecules
B. enantiomers
C. diastereomers
D. different molecules
E. constitutional isomers
Question
H
B
A
The S-isomer is an effective sedative. The R- is a teratogen in
humans, but not rats.
In the structures above, which is the R-isomer, A or
B?
Question
What is the stereochemical designation of the
following molecule?
A. (R)
B. (S)
C. non-chiral (achiral)
Question
What is the stereochemical designation of the indicated
chirality center?
A. (R)
B. (S)
C. non-chiral (achiral)
Question
Indicate the relationship of the pair of
molecules shown.
A. same molecules
B. enantiomers
C. diastereomers
D. different molecules
E. constitutional isomers
Question
Indicate the relationship of the pair of
molecules shown.
A. same molecules
B. enantiomers
C. diastereomers
D. different molecules
E. constitutional isomers
Question: Calculate []D
• A 1.00-g sample is dissolved in 20.0 mL ethanol. 5.00
mL of this solution is placed in a 20.0-cm polarimeter
tube at 25C. The observed rotation is 1.25
counterclockwise.
[]D =
A) -1.25 
B) -6.125 
C)-12.5 
D) +61.25 
Question
A sample of a pure R- enantiomer has a specific rotation of
– 40°. A mixture of R-/S- enantiomers has an observed
optical rotation of + 22°. What is the % ee of the mixture?
A. 55 % ee R
B. 55 % ee S
C. 18 % ee R
D. 0.55 % ee R
E. none of the above
Question
If a sample is 50 % ee of R stereoisomer, what is
the % R in the mixture?
A. 50
B. 100
C. 25
D. 75
Question
If a chemical reaction produces a mixture of 80% R and
20 % S, what is the % ee?
A.
B.
C.
D.
E.
80
60
20
10
4
Question
If a sample of the pure R enantiomer of a molecule has a
specific rotation of – 40° what is the specific rotation of
pure S?
A.
B.
C.
D.
E.
–60°
+60°
–40°
+40°
cannot be determined
Question
If the specific rotation of (R)-2-methylhexan-2-ol is –35°,
what is the specific rotation of (S)-hexan-2-ol?
A.
B.
C.
D.
E.
+35°
–35°
It is negative but value cannot be determined.
It is positive but value cannot be determined.
It cannot be determined.
Question
If a sample of the pure R enantiomer of a molecule has a
specific rotation of – 40° and an enantiomeric mixture of that
molecule has an 82% ee S, what shoulld be the observed
specific rotation of the sample?
A.
B.
C.
D.
E.
+40°
+8.2°
+32.8°
–48.7°
cannot be determined
Question
Calculate the relative proportions of (+)-2-butanol,
[]D = +13.5o, and (-)-2-butanol, []D = -13.5o,
required to give a specific rotation of +0.45o.
A.
B.
C.
D.
E.
50% R : 50% S
90% R : 10% S
3.3 % R : 92.7% S
52% R : 48% S
cannot be determined