Post on 10-Jan-2016
description
MS FARZANA MEHBOOBD.A.NEELUM HIGH SCHOOL
Instructional Lesson
on
ELECTROCHEMISTRY
Overview
• Electrochemistry
introduction
• Cell &Batteries
Electrolysis & its Application
ELECTROCHEMISTRY
FARADAY
From Wikipedia
FOUNDERS
DANIELL
ELECTROCHEMISTRY
ELECTRON TRANSFER REACTIONS
ELECTRIC CURRENT
involves
cause generateOR
Branch of Chemistry
is a
Redox reactions
also called
Redox reactions
Electrochemical reactions
Spontaneous
Galvanic cells
Batteries
Non spontaneous
Electrolytic cells
CONCEPT MAPREDOX REACTIONS
• The loss of electrons is called oxidation,
• The gain of electrons is reduction.
REDUCING OXIDIZING AGENT AGENT
• A redox reaction can be divided into two Half Reactions:
• an oxidation reaction • a reduction reaction.
OIL, Oxidation Is Loss,RIG, Reduction Is Gain
“ An OIL RIG"
This can be easily remembered through:
9
Oxidation-Reduction ReactionsOXIDATION = loss of electrons
Examples:
Na Na+ + e-
Al Al3+ + 3e-
S2- S + 2e-
OXIDATION = increasing the oxidation number (more positive)Example:
NO NO2 -2+2 -2+4
change = +2
+2 to +4 : N is oxidized
Oxid. Nos:
Examples:
Na Na+ + e-
Al Al3+ + 3e-
S2- S + 2e-
OXIDATION-REDUCTION REACTIONS
OXIDATION-REDUCTION REACTIONS
Direct Redox ReactionOxidizing and reducing
agents in direct contact.
Cu(s) + 2 Ag+(aq) ---> Cu2+(aq) + 2 Ag(s)
OXIDATION-REDUCTION REACTIONS
OXIDATION-REDUCTION REACTIONS
Indirect Redox Reaction
A battery
Oxidizing and reducing agents are not in direct
contact
Why do reduction-oxidation reactions occur?
It is all about energy.
Reduction and = an analogous flow oxidation of electrons.
The energy of a chemical system drives the charges to move.
Galvanic cellsElectrochemical cells
Chemical energyElectrical energy
Daniell cell
Redox reaction take place
Voltaic cells1.1 voltage
intoused to convert
in simplest form
has
CONCEPT MAP OF GALVANIC CELL
are
also called
in which
Parts of a Galvanic cell
Two electrodes of different metals
Electrolyte
An electrical wire A salt bridge
Cathode compartment
• The compartment in which reduction occurs.
• The reaction at the cathode: Cu2+ (aq) + 2e- ---> Cu (s)
Cathode electrodeCu
Electrolyte (CuSO4)
Anode compartment
The compartment in which oxidation occurs
The reaction at the anode :
• Zn (s) --->Zn2+ (aq) + 2e-
anode electrodeZn
Electrolyte (ZnSO4)
Story ofAn Ox
&Red Cat
Story ofAn Ox
Red Cat
AND
ANode OXidation
REDuction CAThode
ANODE NEGATIVE DANIEL
Electrolysis
Electro
electricity
and lysisBreak
apart
WHAT IS ELECTROLYSIS
TYPES OF ELECTROLYTE
GENERAL TERMS USED IN ELECTROLYSIS
Electrolytic cell It has three component parts:
1. An electrolyte 2. Two electrodes
(a cathode and an anode).
3. A battery
VIDEO OF ELECTROLYSIS
ELECTROPLATING
EXTRACTION OF
METALS
ANODIZING
ELCTROREFINING
PREPARATION OF ALKALI & CHLORINE
GASIndustrialApplication of electrolysis
Electrolysis of molten Alumina
VIDEO
26
cathode:Au+(aq) +e-→Au
anode:Au→Au+(aq) +e-
external power source
Au
Au+(aq) Au+(aq)
Au
external power source
Gold plating
COPPER REFININGVIDEO
SUMMARY
Concept Map
The End
PRESENTER
MS FARZANA MEHBOOB
D.A.Neelum High School