1. A Review of General Chemistry

Show the direction of the dipole moment in each of the following bonds (use the electronegativities given in [Table 1.3] ):

a. H3C—Br

b. H3C—Li

Which of the following has a bond closest to the ionic end of the bond spectrum?

CH₃NH₂ CH₃CH₃ CH₃F CH₃OH

Which of the following has a polar covalent bond?

CH₃NH₂ CH₃CH₃ CH₃F CH₃OH

Explain why HCl has a smaller dipole moment than HF, even though the H—Cl bond is longer than the H—F bond.

Which of the following has

a. the most polar bond?

b. the least polar bond?

NaI LiBr Cl₂ KCl

Which of the following molecules would you expect to have a dipole moment of zero?

g. BeCl₂

h. BF₃

If the dipole moment of CH₃F is 1.847 D and the dipole moment of CD₃F is 1.858 D, which is more electronegative: hydrogen or deuterium?

Account for the difference in the shape and color of the potential maps for ammonia and the ammonium ion in Section 1.11.

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Rank the bonds from most polar to least polar.

d. C—H, C—C, C—N

Rank the bonds from most polar to least polar.

c. H—O, H—N, H—C

Rank the bonds from most polar to least polar.

b. C—Cl, C—I, C—Br

Which of the following molecules would you expect to have a dipole moment of zero?

d. NH₃

e. H₂C═CH₂

f. H₂C═CHBr

According to the potential map for the ammonium ion <IMAGE>, which atom has the greatest electron density?

Two isomers of 1,2-dichloroethene are known. One has a dipole moment of 2.4 D; the other has zero dipole moment. Draw the two isomers, and explain why one has zero dipole moment.

CHCl=CHCl 1,2-dichloroethene

1. Draw the Lewis structure.

2. Show how the bond dipole moments (and those of any nonbonding pairs of electrons) contribute to the molecular dipole moment.

3. Estimate whether the compound will have a large, small, or zero dipole moment.

g. HCN

h. CH₃CHO

i. H₂C=NH