2SBS (p.151) #9-22

7/14/13

9. Active metals are more difficult to process and refine than less active metals because active metals are more reactive, which causes them to combine and form compounds with other elements.

10. The metals from the Investigating Matter lab would be the easiest to process would be silver and copper because they are less reactive.

11. Most metals exist in nature as minerals rather than as pure metallic elements because most metals are reactive, which causes them to combine with other elements easily which forms compounds or minerals.

12. The reaction that is most likely to occur is (A) calcium metal with chromium (III) chloride. This is because calcium metal is more reactive than chromium chloride, causing calcium to react with chromium in a solution. Basically more reactive metallic elements will form ions in less reactive metallic solution.

13. The equation that represent a reaction that is most likely to occur is (B) because zinc is more reactive than silver, zinc will react within a silver solution to form ions.

14.
   a. It would be a poor idea to stir lead (II) nitrate solution with an iron spoon because since iron is more reactive than lead, it would cause a reaction to form, causing the spoon to possibly dissolve.
   b. A chemical equation to support my answer to a:  Pb2+ + Fe ---> Pb + Fe2+

15. Oxidation is when there is a lose in one or more electrons, causing a cation. Reduction is when there is a gain in one or more electrons, causing a cation to become neutral.

16. a. Au3+ + 3e- ---> Au 
      b. V ---> V4+ + 4e-
      c. Cu+ ---> Cu2+ + 1e-

17. a. reduction
      b. oxidation
      c. reduction

18. a. The reactant that has been oxidized is zinc (Zn) because it is neutral at first, and then the reactant looses two electrons making the product a cation Zn2+.
      b. The reactant that has been reduced is nickel (Ni2+) because at first it is a cation, then the reactant gains two electrons, making the product neutral (Ni).
      c. The reducing agent in this reaction is Zn.

19.  a. The reactant that has been oxidized is potassium 2 K because at first it is neutral, and than the reactant loose an electron, forming a cation of 2 K+.
      b. The reactant that has been reduced is mercury Hg2+ because at first it is a cation, then the reactant gains two electrons, forming a neutral product Hg.
      c. The oxidizing agent in this reaction is Hg2+.

20. a. The oxidation of Al metal by Cr3+ ions: Al + Cr3+ ---> Al3+ + Cr
      b. The reduction of Mn2+ ions by Mg metal: Mn2+ + Mg ---> Mn + Mg2+

21. a. Electrometallurgy converts metal cations to metal atoms by using an electrical current to supply electrons to metal ion, which then reduces the cations.
     b. Pyrometallurgy converts metal cations to metal atoms by treating metals and their ores with heat, which includes the reducing agents known as carbon (coke) and carbon monoxide. These reducing agents provide electrons, which then reduces the cations.
    c. Hydrometallurgy converts metal cations to metal atoms by treating the ores and other metal- containing materials with reactants in a water solution.

22. a. magnesium: pyrometallurgy
      b. lead: pryrometallurgy