p. 151, #9-22

9. Active metals are more difficult to process and refine because they are constantly reacting with the substances around them, making it harder to separate them from their compounds.


10. The metals that would be the easiest to process would be copper and silver because they are the least reactive.


11. Most metals exist in nature as minerals because most metals are reactive.


12. Calcium will most likely react with chromium(III) because it is more reactive than chromium. More reactive substances react with less reactive substances.


13. The first reaction is more likely to occur because the more reactive element is causing the ions of the less reactive element to change to a metal.


14.
a. It would be a bad idea because iron is more reactive than lead, resulting in the decomposition of the spoon.
b.   Pb2+(aq) + Fe(s) à Pb+(aq) + Fe+(s)


15. During reduction, a reactant gains electrons and during oxidation, a reactant loses electrons.


16.
a. Ag3+ + 3e- à Ag
b. Và V4+ + 4e-
c. Cu+ à Cu2+ + e-


17.
a. reduction
b. oxidation
c. reduction


18.
a. Zinc has been oxidized because it has lost electrons.
b. Nickel has been reduced because it has gained electrons.
c. Zinc is the reducing agent


19.
a. Potassium has been oxidized because it has lost an electron.
b. Mercury has been reduced because it gained electrons
c. The oxidizing agent is mercury


20.
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 electric current to add electrons to ions, thus reducing the ion into an atom.
b. Pyrometallurgy uses thermal heat to supply electrons to the ion. Carbon and carbon monoxide serve as the reducing agents.
c. Hydrometallurgy treats ores and other metal containing materials with reactants in a water solution.


22.
a. Electrometallurgy
b. Pyrometallurgy