Sunday, July 14, 2013

HW due Monday, July 15


2SBS #9-22 pg. 151

9.
·      It is much more difficult to process and refine active metals as opposed to less active metals because metals that are more active combine with other elements which then form compounds; however, less active metals stay unconnected.

10.
·      Silver would most likely be the easiest to process since it does not react; thus, it does not combine with other elements or metals.

11.
·      Most elements exist in nature as minerals as opposed to pure metallic elements since they are more reactive.

12.
·      Reaction A is more likely to occur. This is due to the fact that chromium is less reactive than calcium.

13.
·      Reaction B is more likely to occur because zinc is more reactive than silver; thus, putting a reactive metal in a solution that is not reactive would trigger a reaction.

14. 

                A. It wouldn’t be a good idea to stir a solution of lead nitrate with an iron spoon because the iron would cause a reaction since it is more reactive then lead.
                B. Pb2(aq) + Fe(s) à Pb(s) + Fe2(aq)

15.
·      Oxidation means the loss of at least 1 electron that causes a metal to become a cation or an aqueous solution, and reduction is the gain or loss of electrons that causes a cation or aqueous solution to balance out; thus becoming a metal.

16. 

                A. Au3+ + 3e à Au
                B. V à V4+ + 4e-
                C. Cu+ à Cu2+ + e-

17. 
                A. reduction
                B. oxidation
                C. reduction

18. 
                A. Zn was oxidized b/c 2 electrons were lost. It went from a solid to an aqueous solution/
                B. Ni was reduced b/c 2 electrons were gained. It went from an aqueous solution to a solid/metal.
                C. The reducing agent was Zn.

19. 
                A. K+ was oxidized b/c it lost an electron. It became an aqueous solution.
                B. Hg was reduced b/c it gained 2 electrons. It became a solid.
                C. The oxidizing agent was Hg2+.

20. 
                A. Al + Cr3  à Al3 + Cr
                B. Mn2 + Mg à Mn + Mg2

21. 
                A. Electrometallurgy uses an electrical current to decrease metal ions by supplying electrons.
                B. Pyrometallurgy heats metals and ores to change metal cations to atoms.
                C. Hydrometallurgy uses reactants in water solutions to take care of ores and other metal-containing substances.

22. 
                A. Magnesiumà Electrometallurgy.
                B. Leadà Pyrometallurgy.

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