Homework Assignment 15

2SBS #9-22 pg. 151

9. Active metals are more difficult to process and refine than less active metals because more active metals combine with other elements, forming compounds, while less active metals stay unconnected.

10. Silver would be the easiest to process because it is unreactive. This means that it does not combine with other elements and metals.

11. Most elements exist in nature as minerals rather than pure metallic elements because they are more reactive. They combine with other elements and metals, forming compounds and minerals.

12. Reaction A is more likely to occur because chromium is less reactive than calcium.

13. Reaction B would be more likely to occur because zinc is more reactive than silver, and putting a reactive metal in an unreactive solution triggers a reaction.

14. 

• a. It would be a poor idea to stir a solution of lead (II) nitrate with an iron spoon because iron is more reactive than lead and it would cause a reaction.
• b. Pb2(aq) + Fe(s) --> Pb(s) + Fe2(aq)

15. In terms of electron transfer, oxidation means the loss of at least 1 electron, causing a metal to become a cation or aqueous solution, and reduction is the gain or loss of electrons to cause a cation or aqueous solution to balance out and become a metal.

16. 

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

17. 

• a. reduction
• b. oxidation
• c. reduction

18. 

• a. Zn was oxidized because 2 electrons were lost and it went from a solid to an aqueous solution
• b. Ni was reduced because 2 electrons were gained and it went from an aqueous solution to a solid/metal
• c. The reducing agent was Zn

19. 

• a. K+ was oxidized because it lost an electron and became an aqueous solution
• b. Hg was reduced because it gained 2 electrons and became a solid
• The oxidizing agent was Hg2+

20. 

• a. Al + Cr3 --> Al3 + Cr
• b. Mn2 + Mg --> Mn + Mg2

21. 

• a. Electrometallurgy uses an electrical current to reduce metal ions by supplying electrons
• b. Pyrometallurgy heats metals and ores to convert metal cations to atoms
• c. Hydrometallurgy uses reactants in water solutions to treat ores and other metal-containing materials

22. 

• a. Magnesium- Electrometallurgy
• b. Lead- Pyrometallurgy