Monday, July 15, 2013

Homework


2SBS (p.151) #9-22


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

10. silver and copper: they are less reactive
11. Most metals exist in nature as minerals rather than as pure metallic elements because most metals are reactive causing them to easily combine or form compounds with other elements.
12. It is most likely that (A) calcium metal will react with chromium (III) chloride. Because calcium metal is more reactive than chromium chloride, this allows the  calcium to react with chromium in a solution.

13. B:  zinc will react within a silver solution to form ions because it is more reactive than silver.

14.
   a. It would be a poor idea to stir lead (II) nitrate solution with an iron spoon because a chemical reaction could cause the spoon to dissolve since iron is more reactive than lead.
   b. Pb2+ + Fe ---> Pb + Fe2+

15. Oxidation: when 1 or more electrons is lost (forms a cation)
   Reduction: when an elements gains 1 or more electrons (neutralizes the substance)

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

17.   a. reduction
      b. oxidation
      c. reduction

18. a. Zinc has been oxidized because it is neutral at first, but then the reactant looses 2 electrons making the product a cation Zn2+.
      b. Nickle has been reduced because at first it is a cation, but then the reactant gains two electrons and neutralizes the substance.
      c. Zinc is the reducing agent
19.  a. The reactant that has been oxidized is potassium 2 K because it is originally neutral, than the reactant loose an electron and forms a cation of 2 K+.
      b. The reactant that has been reduced is mercury Hg2+ because initially it is a cation, then the reactant gains two electrons creating Hg (a neutralized substance).
      c. Hg2+

20.   a. Al + Cr3+ ---> Al3+ + Cr
      b. Mg ---> Mn + Mg2+

21. a. Electrometallurgy converts metal cations into metal atoms through the use of electrical currents to supply electrons to metal ions which lessen the cations.
     b. Pyrometallurgy converts metal cations to metal atoms by treating metals and their ores with heat, which includes the reducing agents which reduce the cations.
    c. Hydrometallurgy converts metal cations to metal atoms through treating the  ores and other metal- containing materials with reactants in a aqueous solution

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

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