Unit 1 Sec. C Summary HW 3

7/1/14

21) a. i. 68%

ii. 10%

iii. 58%

22) The percent composition gives you the molar mass of the element and is different from the number of atoms in the element.

23) Oxidation is the process of losing of electrons and reduction is the process if gaining electrons.

24) a. Au²⁺ + 2e^– –––> Au

b. V –––> V²⁺ + 2e^–

c. Cu⁺ –––>Cu²⁺ + e^–

25) a. Reduction reaction

b. Oxidation reaction

c. Reduction reaction

26) a. Zinc (Zn) has been oxidized because it lost two electrons.

b. Nickel (Ni) has been reduced because it gained two electrons.

c. Ni is the reducing agent in this reaction.

27) a. Potassium (K) has been oxidized because it lost one electron.

b. Mercury (Hg) has been reduced because it gained two electrons.

c. K is the oxidizing agent in this reaction.

28) a. Al + Cr³⁺ –––> Al³⁺ + Cr

b. Mn²⁺ + Mg –––> Mn + Mg²⁺

29) a. Electrometallurgy uses an electric current to supply electrons to metal ions.

b. Pyrometallurgy involves treating metal and their ore with heat.

c. Hydrometallurgy involves treating ores and metal materials in water solutions.

30) a. Magnesium: Electrometallurgy

b. Lead: Electrometallurgy