Electrochemistry Chapter 21 3 Electrolytic Cells The electrochemical

Electrochemistry Chapter 21. 3

Electrolytic Cells � The electrochemical cells require the INPUT of energy rather than creating energy.

Voltaic Vs Electrolytic Cells Voltaic Cell -The flow of electrons is the result of a spontaneous redox reaction. -Electrical energy is released to power a battery, light, etc. -Electrons flow from anode to cathode -Reduction occurs at cathode -Oxidation occurs at anode 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.

Voltaic Vs Electrolytic Cell

Uses for Electrolytic Cells: � 1) � � 3) Electrolysis of Water 2) Electrolysis of Brine Electrolysis in metal processing

1) Electrolysis of Water

2) Electrolysis of Brine � Brine: Brine A concentration aqueous solution of sodium chloride.

Brine Contn… � To produce chlorine and sodium hydroxide in electrolytic cells, electricity is passed through brine, a sodium chloride solution. Why? Its products have many uses including disinfecting swimming pools, cleaning drains, manufacturing soap, and producing paper pulp.

3) Electrolysis in Metal Processing � It is used to plate, plate purify, purify and refine metals. � A) Electroplating: to plate � B) Electrowinning: impure metals are purified � C) Electrorefining: to refine

Electroplating � 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.

Quick Lab � Page 683 � Perform partner. � Answer with a Questions #1 -3

Assignment: � With a partner, create a study guide to be used for the test. � Test: Tuesday � Notes � Read over 21. 1 -21. 3 pages 678 -679 (Electrolytic VS Voltaic Cells) to help study for the test.