The Foundations of Chemistry

OUTLINE

21-1 Electrical Conduction

21-2 Electrodes

Electrolytic Cells

21-3 The Electrolysis of Molten

Sodium Chloride (the Downs

Cell)

21-4 The Electrolysis of Aqueous

Sodium Chloride

21-5 The Electrolysis of Aqueous

Sodium Sulfate

21-6 Faraday’s Law of Electrolysis

21-7 Commercial Applications of

Electrolytic Cells

Voltaic or Galvanic Cells

21-8 The Construction of Simple

Voltaic Cells

21-9 The Zinc–Copper Cell

21-10 The Copper–Silver Cell

Standard Electrode Potentials

21-11 The Standard Hydrogen

Electrode

21-12 The Zinc–SHE Cell

21-13 The Copper–SHE Cell

21-14 Standard Electrode Potentials

21-15 Uses of Standard Electrode

Potentials

21-16 Standard Electrode Potentials

for Other Half-Reactions

21-17 Corrosion

21-18 Corrosion Protection

Effect of Concentrations (or Partial

Pressures) on Electrode Potentials

21-19 The Nernst Equation

21-20 Using Electrochemical Cells

to Determine Concentrations

21-21 The Relationship of E^0 cellto


G^0 and K

Primary Voltaic Cells

21-22 Dry Cells

Secondary Voltaic Cells

21-23 The Lead Storage Battery

21-24 The Nickel–Cadmium

(Nicad) Cell

21-25 The Hydrogen–Oxygen Fuel

Cell

OBJECTIVES

After you have studied this chapter, you should be able to

• Use the terminology of electrochemistry (terms such as “cell,” “electrode,” “cathode,”
  “anode”)


• Describe the differences between electrolytic cells and voltaic (galvanic) cells


• Recognize oxidation and reduction half-reactions, and know at which electrode each
  occurs


• Write half-reactions and overall cell reactions for electrolysis processes


• Use Faraday’s Law of Electrolysis to calculate amounts of products formed, amounts of
  current passed, time elapsed, and oxidation state


• Describe the refining and plating of metals by electrolytic methods


• Describe the construction of simple voltaic cells from half-cells and a salt bridge, and
  understand the function of each component


• Write half-reactions and overall cell reactions for voltaic cells

Corrosion is an undesirable

electrochemical reaction with very
serious economic consequences. Rust

is formed when iron is oxidized in
the presence of water.