1. A Review of General Chemistry

For each alkene, indicate the direction of the dipole moment. For each pair, determine which compound has the larger dipole moment.

a. cis-1,2-difluoroethene or trans-1,2-difluoroethene

Which compound has the greater electron density on its oxygen atom?

Which compound has the greater electron density on its nitrogen atom?

Which oxygen atom has the greater electron density?

Refer to the electrostatic potential maps <IMAGE> to answer the following questions:

c. Why is the center of the electrostatic potential map of benzene more red than the center of the electrostatic potential map of pyridine?

Which is more reactive, an organolithium compound or an organosodium compound? Explain your answer.

(a) Rank the following bonds in terms of the strength of their bond dipole (1 = weakest, 6 = strongest).

(b) Which carbon has the largest δ⁺ ?

C―F, C―Br, C―I, C―H, C―C, C―Cl

Based on your answer to Assessment 2.22, would you expect a larger atom to be more or less electronegative than a smaller atom?

Given the Lewis structures, indicate the direction of the dipole moment, if there is one.

(e)

Use the symbols δ⁺ and δ⁻ to show the direction of the polarity of the indicated bond in each of the following compounds:

e. HO—Br

f. H₃C—Li

After examining the potential maps for LiH, HF, and H₂, answer the following questions:

<IMAGE>

a. Which compounds are polar?

b. Why does LiH have the largest hydrogen?

c. Which compound has the hydrogen that would be most apt to attract a negatively charged molecule?

Rank the following compounds from highest dipole moment to lowest dipole moment:

Which of the following compounds have a dipole moment of zero?

In what direction is the dipole moment in calicene? Explain.

The C=O double bond has a dipole moment of about 2.4 D and a bond length of about 1.23 Å.

a. Calculate the amount of charge separation in this bond.