Chapter 21.3
The electrochemical cells require the INPUT of energy rather than creating energy.
Voltaic Cell -The flow of electrons is the result of a spontaneous redox reaction. -Electrical energy is released to power a battery, light, etc. Electrolytic Cell -Redox process reaction is NOT spontaneous. -Uses outside source like a battery to input electrical energy to do work like: hydrolysis, electrolysis, and electroplating. -Electrons flow from anode to cathode -Reduction occurs at cathode -Oxidation occurs at anode
1) Electrolysis of Water 2) Electrolysis of Brine 3) Electrolysis in metal processing
Brine Brine: A concentration aqueous solution of sodium chloride.
To produce chlorine and sodium hydroxide in electrolytic cells, electricity is passed through brine, a sodium chloride solution. Why? Why? Its products have many uses including disinfecting swimming pools, cleaning drains, manufacturing soap, and producing paper pulp.
platepurifyrefine It is used to plate, purify, and refine metals. A) Electroplating: to plate B) Electrowinning: impure metals are purified C) Electrorefining: to refine
Electroplating is the deposition of a thin layer of a metal on an object in an electrolytic cell. ◦ Similar to coating with a metal, but this is using electricity to do it. The cathode is the object to be plated. The anode is the plating metal.
Page 683 Perform with a partner. Answer Questions #1-3
With a partner, create a study guide to be used for the test. Test: Tuesday Notes over Read pages (Electrolytic VS Voltaic Cells) to help study for the test.