This document provides an overview of electrochemistry. It begins by defining electrochemistry as the study of chemical reactions at the interface of an electrode and electrolyte involving the interaction of electrical and chemical changes. The document then discusses the history and founders of electrochemistry, including Faraday's two laws of electrolysis. It explains key concepts such as oxidation-reduction reactions, balancing redox equations, and the Nernst equation. The document also covers applications including batteries, corrosion, electrolysis, and branches of electrochemistry like bioelectrochemistry and nanoelectrochemistry.
I Hope You all like it very much. I wish it is beneficial for all of you and you can get enough knowledge from it. Clear and appropriate objectives, in terms of what the audience ought to feel, think, and do as a result of seeing the presentation. Objectives are realistic – and may be intermediate parts of a wider plan.
I Hope You all like it very much. I wish it is beneficial for all of you and you can get enough knowledge from it. Clear and appropriate objectives, in terms of what the audience ought to feel, think, and do as a result of seeing the presentation. Objectives are realistic – and may be intermediate parts of a wider plan.
CONDUCTIVITY-TYPES-VARIATION WITH DILUTION-KOHLRAUSCH LAW - TRANSFERENCE NUMBER -DETERMINATION - IONIC MOBILITY - APPLICATION OF CONDUCTANCE MEASUREMENTS - CONDUCTOMENTRIC TITRATION
This presentation consists of three topics that are:
1. conductance of electrolytic solution
2. Specific Conductance, Molar Conductance & Equivalent Conductance
3. Kohlrausch's Law
Class XII Electrochemistry - Nernst equation.Arunesh Gupta
Introduction, application of electrochemistry, metallic conduction & electrolytic conduction, electrolytes, electrochemical cell & electrolytic cell, Galvanic cell (Daniell cell), Standard reduction & oxidation potential, SHE as reference electrode, Standard emf of a cell or standard cell potential, Electrochemical series & its application, Nernst equation, Relationship between (i) Standard cell potential & equilibrium constant (ii) standard cell potential & standard Gibbs energy, some numerical problems.
A detailed presentation about what is MOT. Explaining its principles, sigma and pi bonds, bond order, and molecular stability. A good and knowledgeable presentation to understand these concepts.
Includes a discussion of Voltaic and electrolytic cells, the Nernst equation and the relationship between electrochemical processes, chemical equilibrium and free energy.
**More good stuff available at:
www.wsautter.com
and
http://www.youtube.com/results?search_query=wnsautter&aq=f
CONDUCTIVITY-TYPES-VARIATION WITH DILUTION-KOHLRAUSCH LAW - TRANSFERENCE NUMBER -DETERMINATION - IONIC MOBILITY - APPLICATION OF CONDUCTANCE MEASUREMENTS - CONDUCTOMENTRIC TITRATION
This presentation consists of three topics that are:
1. conductance of electrolytic solution
2. Specific Conductance, Molar Conductance & Equivalent Conductance
3. Kohlrausch's Law
Class XII Electrochemistry - Nernst equation.Arunesh Gupta
Introduction, application of electrochemistry, metallic conduction & electrolytic conduction, electrolytes, electrochemical cell & electrolytic cell, Galvanic cell (Daniell cell), Standard reduction & oxidation potential, SHE as reference electrode, Standard emf of a cell or standard cell potential, Electrochemical series & its application, Nernst equation, Relationship between (i) Standard cell potential & equilibrium constant (ii) standard cell potential & standard Gibbs energy, some numerical problems.
A detailed presentation about what is MOT. Explaining its principles, sigma and pi bonds, bond order, and molecular stability. A good and knowledgeable presentation to understand these concepts.
Includes a discussion of Voltaic and electrolytic cells, the Nernst equation and the relationship between electrochemical processes, chemical equilibrium and free energy.
**More good stuff available at:
www.wsautter.com
and
http://www.youtube.com/results?search_query=wnsautter&aq=f
Conductors and Non-Conductors
Substances can be classified as conductors and non-conductors based on their ability to conduct electricity.
Conductors: Substances that allow electric current to flow through them are called conductors. For example, Plastic, Wood, etc.
Non-Conductors: Non-conductors are insulators that do not allow electricity to pass through them. For example, Copper, Iron, etc.
Types of Conductors
Conductors are divided into two groups: Metallic conductors and Electrolytes.
Metallic Conductors: These conductors conduct electricity by the movement of electrons without any chemical change during the process. This type of conduction happens in solids and in the molten state.
Electrolytes: They conduct electricity by the movement of the ions in the solutions. It is present in the aqueous solution.
Distinguish between Metallic and Electrolytic Conduction
Metallic Conduction Electrolytic Conduction
The movement of electrons causes the electric current The movement of ions causes the electric current
There is no chemical reaction Ions get ionised or reduced at the electrodes
There is no transfer of matter It involves the transfer of matter in the form of ions
Follows Ohm’s law Follows Ohm’s law
Resistance increases with an increase in temperature Resistance decreases with an increase in temperature
Faraday’s law is not followed Follows Faraday’s law
Electrolytes
(a) Substances whose aqueous solutions allow the conductance of electric current and are chemically decomposed are called electrolytes.
(b) The positively charged ions furnished by the electrolyte are called cations, while the negatively charged ions furnished by the electrolyte are called anions.
Types of Electrolytes
(a) Weak electrolytes: Electrolytes that are decomposable to a very small extent in their dilute solutions are called weak electrolytes. For example, organic acids, inorganic acids and bases etc.
(b) Strong electrolytes: Electrolytes that are highly decomposable in aqueous solution and conduct electricity frequently are called electrolytes. For example, mineral acid and salts of strong acid.
Electrode
For the electric current to pass through an electrolytic conductor, the two rods or plates called electrodes are always needed. These plates are connected to the terminals of the battery to form a cell. The electrode through which the electric current flows into the electrolytic solution is called the anode, also called the positive electrode, and anions are oxidised here.
An electrode through which the electric current flows out of the electrolytic solution is called the cathode, also called the negative electrode, and cations are reduced there.
Electrolysis
Electrolysis is the process of chemical deposition of the electrolyte by passing an electric current. Electrolysis takes place in an electrolytic cell. This cell will convert the electrical energy to chemical energy.
CONTENTS
Electrochemistry: definition & importance
Conductors: metallic & electrolytic conduction,
Electrolytes, Electrochemical cell & electrolytic cell
A simple electrochemical cell: Galvanic cell or (Daniell Cell)
Cell reaction, cell representation, Salt bridge & its use,
Electrode potential, standard electrode potential, SHE,
Standard cell potential or standard electromotive force of a cell
Electrochemical series (Standard reduction potential values)
Nernst Equation, Relationship with Standard cell potential with Gibbs energy & also equilibrium constant
Resistance (R) & conductance (G) of a solution of an electrolyte
Conductivity (k) of solution, Cell constant (G*) & their units,
Molar conductivity (Λm) & its variation with concentration & temperature,
Debye Huckel Onsager equation & Limiting molar conductivity,
Kohlrausch’s law & its application & numerical problems.
Electrolytic cells & electrolysis.
Some examples of electrolysis of electrolytes in molten / aq. state.
Faraday’s laws of electrolysis: First & second law- numerical problems. Corrosion, Electrochemical theory of rusting.
Prevention of rusting.
The definition and types of an electrochemical cell were explained in this ppt. Galvanic and electrolytic cells and their differences are given in this PowerPoint presentation. if you need any other ppt or help[ you can comment.
22CYT12-Unit_I_Electrochemistry - EMF Series & its Applications.pptKrishnaveniKrishnara1
Electrochemistry:Introduction – cells – types - representation of galvanic cell - electrode potential - Nernst equation (derivation of cell EMF) - calculation of cell EMF from single electrode potential - reference electrode: construction, working and applications (Determination of potential of the unknown electrode and pH of the unknown electrode) of standard hydrogen electrode, standard calomel electrode - glass electrode – EMF series and its applications - potentiometric titrations (redox) - conductometric titrations - mixture of weak and strong acid vs strong base.
2. What is
electrochemistry?
Electrochemistry is the study of
chemical reactions which take place at
the interface of an electrode usually a
solid, metal or semiconductor and an
ionic conductor , the electrolyte.
Electrochemistry deals with the
interaction between electrical energy
and chemical change.
3. History of electrochemistry
English chemist john Daniel and physicist
Michael faraday both credited as founders
of electrochemistry today.
The first germen physicist Otto von
Guericke created the electric
generater,which produced static electricity
by applying friction in the machine.
The English scientist William Gilbert spent
17 years experimenting with magnetism
and to a lesser extent electricity.
Michael
faraday
john
Daniel
4. The french chemist charles francois de cisternry du fay
had discovered two types of static electricity.
William Nicholson and Johann Wilhelm Ritter
succeeded in decomposing water into hydrogen and
oxygen by electrolysis.
Ritter discovered the process of electroplating.
William Hyde Wollaston made improvements to the
galvanic cells.
Orsted’s discovery of the magnetic effect of electrical
currents and further work on electromagnetism to
others.
5. Michael Faraday's experiments led him to state his two
laws of electrochemistry and john Daniel invented
primary cells.
Paul Heroult and Charles M.Hall developed an
efficient method to obtain aluminum using
electrolysis of molten alumina.
Nernst developed the theory of the electromotive force
and his equation known as Nernst equation, which
related the voltages of a cell to its properties.
Quantum electrochemistry was developed by Revaz
dogonadeze and his pupils.
6. Oxidation-Reduction
The term redox stands for reduction-oxidation
It refers to electrochemical processes involving
electron transfer to or from a molecule or iron
changing its states.
The atom or molecule which loses electrons is known
as the reducing agent.
The substance which accepts the electrons is called the
oxidizing agent.
10. Standard electrode potential
To allow prediction of the cell potential,
tabulations of standard electrode potential are available.
Tabulations are referenced to the standard hydrogen
electrode.
The standard hydrogen electrode undergoes the reaction
2 H+
(aq) + 2 e– → H2
11. Standard electrode potentials are usually tabulated
as reduction potentials.
The reactions are reversible and the role of particular
electrode in a cell depends on the relative oxi./red.
Potential of both electrodes.
The cell potential is then calculated as the sum of
reduction potential for cathode and the oxidation
potential for anode.
For example, the standard electrode potential for a
copper electrode is:
Cell diagram
Pt(s) | H2 (1 atm) | H+ (1 M) || Cu2+ (1 M) |
Cu(s)
E°cell = E°red (cathode) – E°red (anode)
12. Gibbs free energy and cell
potential
Though cell potential Cell and get electricity n faraday
in the cell:
= -nFEcell
For standard cell, this equation can we written
0= -RTlnK=-nFE0
G
cell
Though produce of electric energy converted into
electric work,
Wmax= Welectrical= -nFEcell
13. Nernst equation
n+|M)=E0
(M
E(M
n+|M)- ln
But solid M concentrate constant
n+|M)=E0
(M
E(M
n+|M)- ln
Example of Daniel cell
2+|Cu)=E0
(Cu
For cathode : E(Cu
2+|Cu)- ln
2+|Zn)=E0
(Zn
For anode : E(Zn
2+|Zn)- ln
2+|Cu) - E(Zn
Cell Potential : Ecell= : E(Cu
2+|Zn)
= E0
2+|Cu)- ln - E0
(Zn
(Cu
2+|Zn)- ln
= Ecell=E0
cell- ln
14. Electrical resistivity
It is an intrinsic property that quantities how strongly a
given material opposes the flow of electrical current.
Many resistors and conductors have a uniform cross
section with a uniform flow of electric current and made
of one material
The electrical resistivity defined
15. Electrical conductivity
The reciprocal of electrical resistivity, and measures a
material’s ability to conduct an electric current.
It is commonly represented by σ
Conductivity is defined as
Conductivity SI units of Siemens per meter.
16. Molar conductivity
Molar conductivity is defined as the conductivity of an
electrolyte solution divided by the molar
concentration of the electrolyte, and so measures the
efficiency with which a given electrolyte conducts
electricity in solution.
From definition, the molar conductivity
17. • Two cases should be distinguished:
Strong eletrolyte and weak electrolyte
For strong electrolyte
Salts, strong acids and strong bases, the molar
conductivity depends only weakly on concentration.
18. For weak electrolyte
The molar conductivity strongly depends on
concentration.
The more dilute a solution, the greater its molar
conductivity, due to increased ionic dissociation.
For weak electrolyte obeys Oswald's dilulation law.
19. Kohlrausch’s law of independent
migration of ions
High accuracy in dilute solutions, molar conductivity
is composed of individual contributions of ions.
Limiting conductivity of anions and cations are
additive, the conductivity of a solution of a salt is equal
to the sum of conductivity contributions from the
cation and anion
Λ0
m=v+ Λ0
+ + v- Λ0
-
20. Battery
Many types of battery have been commercialized and
represent an important practical application of
electrochemistry.
Early wet cells powered the first telegraph and
telephone systems, and were the source of current for
electroplating.
The zinc-manganese dioxide dry cell was the first
portable, non-spill able battery type that made
flashlights and other portable devices practical.
21. The mercury battery using zinc and mercuric oxude
provided higher levels of power and capacity than the
original dry cell for early electronic devices.
Lead-acid battery was secondary battery.
The electrochemical reaction that produced current
was reversible, allowing electrical energy and chemical
energy to be interchanged as needed.
Lead-acid cells continue to be widely used in
automobiles.
22. The lithium battery, which does not use water in the
electrolyte, provides improved performance over other
types.
Rechargeable lithium ion battery is an essential part of
many mobile devices.
23. Corrosion
Corrosion is the term applied to steel rust caused by an
electrochemical process.
Corrosion of iron in the form of reddish rust, black
tarnish on silver, red or green may be appear on copper
and its alloys, such as brass.
24. Prevention of corrosion
Coating
Metals can be coated with paint or other less
conductive metals.
This prevents the metal surface from being exposed to
electrolytes.
Scratches exposing the metal substrate will result in
corrosion.
25. • Sacrificial anodes
The method commonly used to protect a structural
metal is to attach a metal which is more anodic than
the metal to be protected.
This forces the structural metal to be catholic thus
spared corrosion. it is called sacrificial.
Zinc bars are attached to various locations on steel
ship hulls to render the ship hull catholic.
Other metal used magnesium.
26. Electrolysis
The spontaneous redox
reactions of a conventional
battery produce electricity
through the different chemical
potentials of the cathode and
anode in the electrolyte.
Electrolysis requires an
external source of electrical
energy to include a chemical
reaction , and this process
takes place in a compartment
called an electrolytic cell.
27. Electrolysis of molten sodium
chlorine When molten, the salt sodium chloride can be
electrolyzed to yield metallic sodium and gaseous
chlorine.
This process takes place in a special cell named
Down’s cell.
Reactions that take place at Down's cell are the following
Anode (oxidation): 2 Cl– → Cl2(g) + 2 e–
Cathode (reduction): 2 Na+
(l) + 2 e– → 2 Na(l)
Overall reaction: 2 Na+ + 2 Cl–
(l) → 2 Na(l) + Cl2(g)
This process can yield large amounts of metallic
sodium and gaseous chlorine, and widely used on
mineral dressing and metallurgy industries.
28. Quantitative electrolysis and
Faraday’s law
Quantitative aspects of electrolysis were originally
developed by Michel faraday .
Faraday is also credited to have coined the terms
electrolyte.
Electrolysis among many others while studying
analysis of electrochemical reactions.
Faraday advocate of the law of conservation of energy.
29. First law
The mass of products yielded on the electrodes was
proportional to the the value of current supplied to the cell,
the length of time the current existed, and the molar mass
of the substance analyzed.
The amount of substance deposited on each electrode of an
electrolytic cell is directly proportional to the quantity of
electricity passed through the cell.
m=
30. Second law
The amounts of bodies which are equivalent to each
other in the ordinary chemical action have equal
quantities of of electricity naturally associated with
them.
The quantities of different elements deposited by a
given amount of electricity are in the ratio of the
chemical equivalent weights
31. Applied aspects of
electrochemistry
Industrial electrolytic processes
Electrochemical Reactors
Batteries
Fuel cells
Some Electrochemical Devices
Electrochemical Methods of Analysis
32. Branch of electrochemistry
Photo electrochemistry
It is subfield of study within physical chemistry.
The interest in this domain is high in the context of
development of renewable energy conversion and
storage technology.
The effects of luminous radiation on the properties of
electrodes and on electrochemical reactions are the
subject of photo electrochemistry
33. Semiconductor’s electrochemistry
Semiconductor material has a band gap and generates a
pair of electron and hole per absorbed photon if the
energy of the photon is higher than the band gap of the
semiconductor.
This property of semiconductor materials has been
successfully used to converted solar energy into electrical
energy by photovoltaic devices.
Semiconductor-electrolyte interface
When a semiconductor comes into contact with a liquid,
to maintain electrostatic equillibrium
There will be a charge transfer between the
semiconductor and liquid phase,if formal redox potential
of redox species lies inside semiconductor band gap.
34. At thermodynamic eqilibrium, the fermi level of
semiconductor and the formal redox potential of redox
species and between interface semiconductor.
This introduce n-type semiconductor and p-type
semiconductor.
This semiconductor used as photovoltaic device similar to
solid state p-n junction devices.
Both n and p type semiconductor can used as photovoltaic
devices to convert solar energy into electrical energy and
are called photoelectrical cells
35. Boielectrochemistry
It is branch of electrochemistry and biophysical
chemistry concerned with topics like cell electron-proton
transport, cell membrane potentials and
electrode reactions of redo enzymes.
Bioelectrochemistry is a science at the many junctions
of sciences.
36. Nanoelectrochemistry
Nanoelectrochemistry is a branch of electrochemistry
that investigates the electrical and electrochemical
properties of materials at the nanometer size regime.
Nanoelectrochemistry plays significant role in the
fabrication of various sensors, and devices for detecting
molecules at very law concentrations.
37. The term electrochemical nanostructuring can be used
to mean different things.
This term is employed to refer to generation at will of
nanostructure on electrode surface, involving a given
positioning with a certain precision
The term nanostructure is used to describe the
generation of nanometric patterns with move or less
narrow size distribution and a periodic or random
ordering on the surface.
But without control on the spatial location of the
nanostructure.
38. Application of electrochemistry
There are various extremely important electrochemical
processes in both nature and industry.
The coating of objects with metals or metal oxides
through electro deposition and the detection of alcohol in
drunken drivers through the redox reaction of ethanol.
Diabetes blood sugar meters measure the amount of
glucose in the blood through its redox potential.
39. The generation of chemical energy through
photosynthesis in inherently an electrochemical process.
Production of metals like aluminium and titanium from
their ores.
For Photo electrochemistry
Artificial photosynthesis
Regenerative cell or Dye-sensitized cell
Photo electrochemical splitting of water
40. For Boielectrochemistry
Some of different experimental techniques that can be
used to study bioelectrochemical problems.
Ampermetic of biosensors
Biofuel cells
Bioelectrosynthesis