Chapter 10

 

1.  Identify each of the following as an oxidation or reduction reaction.

a.  Zn²⁺ + 2e^– ---> Zn

b.  Cu ---> Cu²⁺ + 2e^–

c.  Fe ---> Fe³⁺ + 3e^–

d.  I₂ + 2e^– ---> 2I^–

 

2. Why can Earth’s atmosphere be described as an oxidizing atmosphere?

 

3.  Indicate whether following reactions are strong, weak, or nonelectrolytes:

a.       K₂SO₄(s) (in H₂O) ---> 2K⁺(aq) + SO₄^2-(aq)

b.      NH₄OH(aq) (in H₂O) <---> NH₄⁺ (aq) + OH^-(aq)

c.       C₆H₁₂O₆(s) (in H₂O) ---> C₆H₁₂O₆(aq)

d.      MgCl₂(s) (in H₂O) ---> Mg²⁺(aq) + 2Cl^-(aq)

 

4. Would you expect a piece of iron to rust on the surface of the moon?  Explain.

 

5. Besides electricity, what do the fuel cells used on the space shuttle produce?

 

6. Oxygen in the air reacting with substances in food can cause spoilage.  Why are antioxidants added to food?

 

7. In addition to iron, what reactants are needed for the formation of rust?

 

8. Tell which substance is reduced and which is oxidized in the following equations.

a. 2Al(s) + 3Cl₂(g) ---> 2AlCl₃(s)

 

b. S(s) + O₂(g) ---> SO₂(g)

 

c. CuO(s) + H₂(g) ---> Cu(s) + H₂O(g)

 

d. C₂H₄(g) + H₂(g) ---> C₂H₆(g)

 

9. The main source of magnesium in seawater is Mg²⁺ ions.  Is this magnesium in an oxidized or reduced form?

 

10. There are how many equivalents in the following ions:

a. 1 mole of Cu²⁺

b. 1 mole of Br^-

c. 2 mole of Na⁺

d. 1 mole of N^3-