April 04, 2013 -One of the main uses of electrolysis is the production of pure elements from compounds -In 1808 Sir Humphrey Davy used electrolysis to discover Mg, Ca, Sr, and Ba -when trying to purify elements from solution, water can interfere with the reaction because often it is the SOA or SRA -to avoid interference from water, the compound can be melted, and the molten compound can act as the electrolyte (but this is difficult) The Electrolysis of Potassium The Electrolysis of Molten Chloride Solution Potassium Chloride April 04, 2013 The Electrolysis of Potassium The Electrolysis of Molten Chloride Solution Potassium Chloride Industrial Applications of Electrolysis April 04, 2013 Chlor-Alkali Cell A Downs Cell April 04, 2013 The Hall-Heroult Process The Refining of Aluminum Precious Metal No one knew about aluminum until 1825. That’s when a Danish chemist first extracted pinhead-sized bits of aluminum from a mineral called alumina. In 1884, aluminum was even chosen for a place of honor at the very tip of the Washington Monument, because it was such a rare metal. But, extracting aluminum from alumina was very difficult, and for most of the 1800s, aluminum was rare and expensive. It was so valuable that kings and queens had fine tea sets and ornamental objects made of aluminum. April 04, 2013 To refine aluminum using electrolysis, Al2SO4 was dissolved in a mineral called cryolite Hall's Original Samples of Aluminum April 04, 2013 Metal Plating -plating involves covering a metal object with a thin coating of another metal Examples: chrome bumpers, jewelry -the object to be plated is placed at the cathode -the anode contains the metal that will be plated (usually) -the electrolyte contains the ion of metal that will be plated A copper spoon is plated with silver Why should the cell be turned on before the spoon is connected? April 04, 2013 Refining Metals Through Electrolysis cathode: pure metal anode: impure metal -the anode dissolves and the pure metal is plated at the cathode April 04, 2013 Assignment: Read Section 13.3 of your textbook. Do questions 7 and 8 on page 508, and questions 17-20 on page 510 April 04, 2013.