1. A Review of General Chemistry

For the molecules shown, indicate the direction of the dipole moment.

(b)

For the molecules shown, indicate the direction of the dipole moment.

(a)

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

(a)

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

(b)

Carbon dioxide (CO₂) has no dipole moment (μ = 0 D). The related molecule sulfur dioxide (SO₂) does have a dipole moment (μ = 1.6 D) Explain this observation.

Using only your intuition, rank the following covalent bonds in terms of their polarity (1 = most polar; 6 = least polar). [You can use the periodic trend of electronegativity, but don't use actual numbers.]

(a) C―C

(b) C―O

(c) C―H

(d) C―F

(e) C―Cl

(f) C―S

Rank the following elements from least electronegative to most electronegative.

Na, Si, F, Mg, C, O, N

(i) Using the periodic trend, choose the more electronegative atom in each pair. For one pair, you'll need to look at the actual Pauling values. (ii) For which one? (iii) Why?

(b) N vs. O

(i) Using the periodic trend, choose the more electronegative atom in each pair. For one pair, you'll need to look at the actual Pauling values. (ii) For which one? (iii) Why?

(d) B vs. Si

In each pair of atoms, which has the larger atomic radius? Which is more electronegative?

(c) O vs. S

In each pair of atoms, which has the larger atomic radius? Which is more electronegative?

(b) C vs. O

Which bond is stronger? Briefly explain why.

b.

Which bond is stronger? Briefly explain why.

a.

For each pair of compounds, predict which one has the higher molecular dipole moment, and explain your reasoning.

a. ethyl chloride or ethyl iodide

b. 1-bromopropane or cyclopropane

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