Question

Chapter 11:

1. What is a prime rule in naming alkenes?

a. Find the longest carbon chain.

b.Find the longest carbon chain containing the alkene.

c. Find whether the alkene has a cis- or trans- configuration.

d.Find how far the alkene functionality is from either end.

2. What is the IUPAC name of the following alkene?

a. cis-5-methyl-2-heptene

b. trans-2-ethyl-4-hexene

c. trans-5-methyl-2-heptene d. trans-3-methyl-5-heptene

3. What is the hybridization, geometry, and bond angle of the carbon marked by an asterisk?

*

a. sp2, tetrahedral, 109.5° b.sp3, trigonal planar, 120° c. sp3 , tetrahedral, 180° d.sp2, trigonal planar, 120°

4. Double bonds are made from which combination of bonds?

a. one sigma bond

b.one pi bond

c. two sigma bonds and one pi bond d.one sigma and one pi bond

5. Which is generally more polar, cis-alkenes or trans-alkenes?

a. cis-alkenes

b. trans-alkenes

c. The polarity of the alkene will depend on the substituents present.

d.There is no correlation between cis- and trans- stereochemistry and molecular polarity.

6. Which is generally more stable, cis-alkenes or trans-alkenes?

a. cis-alkenes

b. trans-alkenes

c. The stability of the alkene will depend on the substituents present.

d.There is no correlation between cis- and trans- stereochemistry and molecular stability.

7. Which statement is true with respect to the following two alkenes?

a. I. has E stereochemistry, while II. has Z stereochemistry.

b. I. has Z stereochemistry, while II. has E stereochemistry.

c. Both I. and II. have E stereochemistry.

d. Both I. and II. have Z stereochemistry.

8. What is the difference between vicinal and geminal substituents on an alkene?

a. Two of the three configurations of geminal and vicinal must relate to different side substituents.

b. Of all the configurations, only geminal has substituents on two carbons.

c. Of all the configurations, only vicinal has substituents on a single carbon.

d. Of all the configurations, only geminal has substituents on a single carbon.

9. Which of the following correctly orders the coupling constants typically observed for alkenes in 1H-NMR?

a. Jgem < Jcis < Jtrans

b. Jcis < Jgem < Jtrans

c. Jcis < Jtrans < Jgem

d. Jgem = Jcis = Jtrans

10. Infrared spectroscopy involves what molecular phenomenon?

a. nuclear spin alignment

b. The absorption of infrared radiation by the

magnetic poles of a molecule.

c. excitation between ground and excited vibrational states

d. excitation between ground and excited rotational states

11. How can a mass spectrometer determine molecular formulas?

a. By separating molecules based on a charge to mass ratio

b.By separating molecules based on charge and polarity

c. By separation of molecules by the number of carbon atoms present

d.By separating molecules based on molecular mass

12. When in a mass spectrometer, where does fragmentation occur most preferentially within a molecule?

a. at highly substituted carbon centers

b.at the - CH2 - linkages in carbon chains

c. at heteroatom - carbon bonds

d.at the ends of a molecule

13. What is a molecule’s degree of unsaturation?

a. the number of rings in a molecule

b.the sum of the number of pi bonds and rings in a molecule

c. the number of pi bonds minus the number of rings in a molecule

d.the sum of the number of rings, pi bonds, and terminal points in a molecule

There are ___ degrees of unsaturation present in the following molecule of amoxicillin?

a.6 b.7 c. 8 d.9

15. Determine the degrees of unsaturation for a compound with a molecular formula of C6H12N2Cl2.

a.1 b.2 c. 3 d.4

16. Why are trans- alkene isomers generally more stable than cis- alkene isomers?

a. because trans- alkenes exhibit less steric crowding b.because trans- alkenes have more tertiary carbon

centers

c. because cis- alkene isomers fragment more easily upon substitution

d.because of hyperconjugation found only in trans- alkenes.

17. What are two broad methods for the preparation of alkenes?

a. alcohol dehydration and catalyzed reduction b.haloalkane elimination and catalyzed reduction c. loss of hydrohalides and solvolysis d.haloalkane elimination and alcohol dehydration

18. How does Saytzev’s rule apply to

the synthesis of alkenes via E2

elimination?

a. The major product of the reaction will be the least highly substituted alkene.

b. The major product of the reaction will be the most highly substituted alkene.

c. The transition state will be stabilized by eclipsed geometry of the abstracted proton and the leaving group.

d. The least and most highly substituted products will be formed in equimolar amounts.

Answer 1