9. Active metals are more difficult to process and refine than are less active metals because active metals are more reactive; therefore, they have the ability to combine and form compounds with other elements. On the other hand, since less active metals are less reactive, they are less difficult to process and refine which is why gold and silver were excellent materials for decorative and useful objects.
10. Silver would be the easiest to process because of it's lack of reactivity.
11. Most metals exist in nature as minerals rather than pure metallic elements, because since most metals are reactive, they combine with other elements to form compounds, or minerals.
12. A reaction between calcium metal with chromium (III) chloride is more likely to occur because calcium is more reactive than chromium chloride and because it is more reactive, it would cause a reaction.
13. Equation A represents a reaction that is more likely to occur because zinc is more reactive than silver, so that would cause a reaction.
14.
a. Stirring a solution of lead (II) nitrate with an iron spoon would cause a reactive, since iron is more reactive than lead.
b.Pb^2+ + Fe ---> Pb + Fe^2+
15. Oxidation is the loss of one more more electrons that causes a metal to become a cation or aqueous solution. Reduction is the gain of one more more electrons that causes a cation/aqueous solution to balance its electrical charge and become a metal.
16.
a. Au^3+ + 3e^- ---> Au
b. V ---> V^4+ + 4e^-
c. Cu+ ---> Cu^2+ + 1e^-
17.
a. reduction.
b. oxidation.
c. reduction.
18.
a. Zn^2+ has been oxidized. Zn loses two electrons to become a cation/aqueous solution, Zn^2+.
b. Ni has been reduced. Ni^2+ gains two electrons to essentially rebalance its charge and become a metal/solid as Ni.
c. The reducing agent in this reaction is Zn.
19.
a. K^+ has been oxidized. K loses an electron to become a cation/aqueous solution, K^+.
b. Hg has been reduced. Hg^2+ gains two electrons to essentially rebalance its charge and become a metal/solid as Hg.
c. The oxidizing agent in this reaction is Hg^2+.
20.
a. Al + Cr^3+ ---> Al^3+ + Cr
b. Mn^2+ + Mg ---> Mn + Mg^2+
21.
a. Electrometallurgy is the use of an electrical current to supply electrons to metal ions, this reducing them.
b. Pyrometallurgy is the treatment of metals and their ores with heat (thermal energy), as in a blast furnace. Carbon (coke) and carbon monoxide are common reducing agents, for they provide electrons, thus reducing the metal ions.
c. Hydrometallurgy is the treatment of ores and other metal-containing materials with reactants in water solution. It is used to recover silver and gold from old mine tailings by a process known as leaching.
22.
a. Electrometallurgy.
b. Pyrometallurgy
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