Problem set

Please label the questions with the appropriate numbers to avoid
confusion.

2. Which half-reactions represent oxidation and which reduction? Explain
your reasoning.

2+ -

a. Fe ( Fe + 2 e

4+ _ 2+

b. Ni + 2 e ( Ni

- -

c. 2 H O + 2 e ( H + 2 OH

2

4. Explain the difference between a rechargeable battery and one that
must be discarded. Contrast a NiCad battery with an alkaline battery in
your explanation.

7. Two common units associated with electricity are volts and amps. What
does each unit measure?

14. What is the difference between a storage battery and a fuel cell?

3. Some people object to synthetic polymers, saying that polymers are
not “natural.� Give example of two natural polymers.

12. This is a representation of a small segment of polyethylene. The
hydrogen atoms are omitted for the sake of clarity.

I I I I

I I I I

I I I I

---C----C---C---C---

I I I I

I I I I

I I I I

I I I I

Does this representation predict that the carbon-to-carbon-to-carbon
bond angles in polyethylene are all 180 degrees? Explain your reasoning.

19. The structure for the styrene monomer:

H H

\ /

C == C

/ \

H (a pentagon with a circle inscribed in the middle)

Rewrite this shorthand structure showing all of the atoms.

What is the molecular formula for styrene?

What is the molar mass of a polystyrene molecule consisting of 5000
monomer units?