1. Stereochemistry
Quiz #4

2. Question The molecules above are (Z) configurations.
True (A) False (B) 27

3. 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

4. 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

5. Question
Both cis- and trans-1,2-dimethylcyclohexane are chiral. True (A) False (B)

6. Question
How many of the following compounds contain an internal mirror plane of symmetry?
A) 1
B) 2
C) 3
D) 4

7. Question
Which of the following molecules is chiral? B A C D

8. What is the stereochemical designation of the following molecule?
Question
What is the stereochemical designation of the following molecule?
 A. (R) B. (S) C. non-chiral (achiral)

9. Question
 Indicate the relationship of the pair of molecules shown.
A. same molecules B. enantiomers C. diastereomers D. different molecules E. constitutional isomers

10. Indicate the relationship of the pair of molecules shown.
Question
Indicate the relationship of the pair of molecules shown.
A. same molecules B. enantiomers C. diastereomers D. different molecules E. constitutional isomers

11. Indicate the relationship of the pair of molecules shown.
Question
 Indicate the relationship of the pair of molecules shown.
A. same molecules B. enantiomers C. diastereomers D. different molecules E. constitutional isomers

12. Indicate the relationship of the pair of molecules shown.
Question
 Indicate the relationship of the pair of molecules shown.
A. same molecules B. enantiomers C. diastereomers D. different molecules E. constitutional isomers

13. Indicate the relationship of the pair of molecules shown.
Question
Indicate the relationship of the pair of molecules shown.
A. same molecules B. enantiomers C. diastereomers D. different molecules E. constitutional isomers

14. Question In the structures above, which is the R-isomer, A or B? H B A
Figure Number: UN
Title: Thalidomide
Caption: Structural formula and ball-and-stick model of thalidomide showing chiral carbon.
Notes: The l isomer of thalidomide is a severe teratogen, whereas the d isomer is only a mild teratogen.
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?

15. What is the stereochemical designation of the following molecule?
Question
 What is the stereochemical designation of the following molecule?
A. (R) B. (S) C. non-chiral (achiral)

16. Question
 What is the stereochemical designation of the indicated chirality center?
 A. (R) B. (S) C. non-chiral (achiral)

17. Indicate the relationship of the pair of molecules shown.
Question
Indicate the relationship of the pair of molecules shown.
A. same molecules B. enantiomers C. diastereomers D. different molecules E. constitutional isomers

18. Indicate the relationship of the pair of molecules shown.
Question
Indicate the relationship of the pair of molecules shown.
A. same molecules B. enantiomers C. diastereomers D. different molecules E. constitutional isomers

19. Question: Calculate []D
A 1.00-g sample is dissolved in 20.0 mL ethanol 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)  B)  C)-12.5  D) 

20. 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 % ee R E. none of the above

21. 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

22. Question
 If a chemical reaction produces a mixture of 80% R and 20 % S, what is the % ee? 80 60 20 10 4

23. Question –60° +60° –40° +40° cannot be determined
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?
–60°
+60°
–40°
+40°
cannot be determined

24. Question +35° –35° It is negative but value cannot be determined.
 If the specific rotation of (R)-2-methylhexan-2-ol is –35°, what is the specific rotation of (S)-hexan-2-ol?
+35°
–35°
It is negative but value cannot be determined.
It is positive but value cannot be determined.
It cannot be determined.

25. 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?
+40°
+8.2°
+32.8°
–48.7°
cannot be determined

26. 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.
50% R : 50% S
90% R : 10% S
3.3 % R : 92.7% S
52% R : 48% S
cannot be determined