utilizes electrical energy to create chemical energy Electrolytic Cells utilizes electrical energy to create chemical energy

Electrolytic Cells electricity used to force non-spontaneous reactions to occur endothermic electrolytic cells identified by presence of battery or power supply

galvanic/Voltaic cell chemical potential energy electrical potential energy electrolytic cell

Electrolytic Decomposition of H2O H2 produced at one electrode, O2 at other 2H2O + energy 2H2 + O2 Can you tell from the picture the side where H2 is produced? Where O2 is produced?

electrolytic cell works in reverse of a galvanic cell this time: Zn is cathode; where reduced takes place & Cu is anode; where oxidation takes place

two types of electrolytic cells 1. Fused Salt Cells – used to purify metals (fused means melted!) 2. Electroplating Cells – designed to cover a surface with metal so will have specific properties

Electroplating move desired coating from anode onto object to be plated solution contains ions of element to be plated - in this case Cu+2

Can Cu be plated onto Al? Al above Cu in Table J reaction will not happen spontaneously so… external energy source (power supply or battery) needed to force reaction to occur

An Ox ate a Red Cat anode: electrode at which oxidation occurs cathode: electrode at which reduction occurs electrode polarity opposite than galvanic cell! anode is POSITIVE cathode is NEGATIVE

A POX on Electrolytic Cells Anode – Positive – Oxidation electrolytic cell: polarity determined by outside power supply anode is attached to (+) terminal cathode is attached to (-) terminal

(+) (-) (+) (-) Battery anode: where oxidation happens Cu  Cu+2 + 2e- cathode: obj being plated - where reduction happens Cu+2 + 2e-  Cu Cu(s) Cu+2 SO4-2 Note: just moving Cu around

Plating cathode: object to be plated anode: made of metal want to plate on object solution: contains ions of plating metal Plating

purify metals from their ores Fused Salt Cells: used to Why does NaCl have to be molten? To which electrode will Na+1 ions be attracted to? To which electrode will Cl-1 ions be attracted to? ox: 2Cl-1  Cl2 + 2e- red: Na+1 + 1e-  Na