16. What types of chemical reaction do alkanes most commonly undergo?
What are the principal reactions of alkenes?
17. Why is the E,, for alkane reactions inherently higher than
18. What are electrophiles and nucleophiles? In the base-catalyzed
hydrolysis of ethyl acetate, is the attacking group an electrophile,
or a nucleophile? What determines which end of the carbonyl C~O
bond this group attacks?
19. What is Markovnikov's rule, and what does it tell us about
the products formed in alkene reactions?
20. How is ethylene the basis for a large family of plastics? What
is the corresponding parent molecule for rubbers?
21. What effect does cross-linking have on the physical properties
of plastics and rubbers?
22. What are the cis and trans isomers of polybutadiene called?
How does their molecular structure account for their differences
in physical properties?
23. How does entropy contribute to the elasticity of rubber?
24. What is conjugation in molecules? What does it do to electronic
25. What is aromaticity and how is it related to conjugation? What
is the most common small aromatic molecule?
26. Why does the extent of delocalization in conjugated and aromatic
molecules affect the light-absorbing properties of the molecule?
How is this property put to use in living organisms? Name a linear
conjugated molecule and a ring compound that are used as lightgathering
molecules by green plants.
27. How does a change in the size of the delocalized system change
the wavelength of light absorbed in green and purple bacteria? How
does this absorption contribute to the names of these classes of
28. Why is addition of a molecule across a double bond of the ring
an unfavorable reaction for benzene, compared with substitution
around the edge of the ring?