Unit 2: Section B summary: 9-22 p. 151-2

          

9.    Active metals are more difficult to process and refine because they will be harder to separate from their compounds.

10.Copper and silver would be the easiest to process because they are the least reactive out of the four metals we investigated.

11.Most metals exist as minerals rather than pure metallic elements because most of them are very reactive.

12.Calcium will react with chromium chloride, rather than the other way around because in general a more reactive metallic element will react with a less reactive element.

13. The (a) equation will most likely occur because a more reactive element will cause the ions of the less reactive element to change to their corresponding metal.

14.

a.    That would be a poor idea because iron is more reactive than lead, which means the iron metal of the spoon will corrode or dissolve.

b.    Pb2+(aq) + Fe(s) à Pb+(aq) + Fe+(s)

15. Reduction is a chemical change in which a reactant can be considered to gain one or more electrons. Oxidation is a chemical change where a reactant loses one or more electrons.

16. Equations:

a.    Ag3+ + 3e- à Ag

b.    Và V4+ + 4e-

c.    Cu+ à Cu2+ + e-

17.   Oxidation or Reduction:

a.    Reduction

b.    Oxidation

c.    Reduction

18. Zn(s) + Ni2+(aq) à Zn2+(aq) + Ni(s)

a.    Zinc has been oxidized because it has lost electrons.

b.    Nickel has been reduced because it gained electrons.

c.    The reducing agent is the zinc.

19. 2 K(s) + Hg2+(aq) à 2 K+(aq) + Hg(s)

a.    Potassium has been oxidized because it lost an electron.

b.    Mercury has been reduced because it gained electrons.

c.    Mercury.

20.  More Equations:

a.    Al(s) + Cr3+(aq) à Al3+(aq) + Cr(s)

b.    Mn2+(aq) + Mg(s) à Mn(s) + Mg2+(aq)

21.

a.    Electrometallurgy uses an electrical current to supply electrons to metal ions, thus reducing them.

b.    Pyrometallurgy involves the treating of metals and their pres with heat, as in a blast furnace. The reducing agents, such as carbon and carbon monoxide, provide electrons thus causing the metal ions to be reduced.

c.    Hydrometallurgy is the treating of ores and other metal-containing materials with reactants in a water solution.

22.

a.    With magnesium it is most helpful to use electrometallurgy,

b.    For lead, pyrometallurgy is most useful.