HCM INTERNATIONAL UNIVERSITY SCHOOL OF BIOTECHNOLOGY. APPLICATIONS OF ELECTROCHEMISTRY. Course: ANALYTICAL CHEMISTRY Lecturer: Dr. NGUYEN TUAN KHOI. MEMBERS OF GROUP. Ph ạm Nguyễn Huệ Nh ân Thái V ă n Ch í Nguyễn Th ị Ph ươ ng Thùy Trần Đỗ Ngọc Oanh V õ Hoàng Lâm
HCM INTERNATIONAL UNIVERSITYSCHOOL OF BIOTECHNOLOGY
Course: ANALYTICAL CHEMISTRY
Lecturer: Dr. NGUYEN TUAN KHOI
Ph ạm Nguyễn Huệ Nh ân
Thái Văn Ch í
Nguyễn Th ị Phương Thùy
Trần Đỗ Ngọc Oanh
V õ Hoàng Lâm
Nguyễn Th ị Thu Cúc
Trương Thị Ngọc Nhi
Lê Trần Khánh Trang
Đỗ Vân Khanh
T ôn Th ị H ồng Th ảo
Nguy ễn Vi ệt Th ư
Nguy ễn Ng ọc Y ên Nhi
Đ oàn T ây Nguy ên
Nguy ễn Duy Trung
Nguy ễn Đ ức Thanh Long
V ũ Ng ọc C ư ơng
Nguyễn Vũ Nh ất Th ịnh
II. Electrochemical cells
III. Electrochemical cell applications
IV. Electrochemical methods
Ox1 + red2 red1 + ox2
What about the sign of the electrodes?
What about half-cell reactions?
Cu+2 + 2e- Cu
Zn Zn+2 + 2e-
plates out or deposits on electrode
Zn electrode erodes
What happened at each electrode?
1.0 M CuSO4
1.0 M ZnSO4
Zn (s) + Cu2+(aq) Cu (s) + Zn2+(aq)
a. Galvanic cells
Anode (Ox) : Zn(s) = Zn2+ + 2e
Cathode (Red) : Cu2+ + 2e = Cu (s)
Net reaction : Zn (s) + Cu2+ = Zn2+ +Cu (s)
Zn (s) | Zn2+ (1 M) || Cu2+ (1 M) | Cu (s)
Primary battery has long been known as dry-cell. It cannot be recharged. It’s widely used to power flashlight and some other similar devices.
The first practical battery consisted of a stack of small electrical cell, each consisting of a silver plate and a zinc plate separated by a sheet of cardboard which had been soaked in salt water
The electrode reactions are
Zn → Zn2+ + 2e–
2 MnO2 + 2H+ + 2e– → Mn2O3 + H2O
A secondaryorstorage battery is capable of being recharged. Its electrode reactions can proceed in either direction.
During charging, electrical work is done on the cell to provide the free energy needed to force the reaction in the non-spontaneous direction.
Conventional batteries supply electrical energy from the chemical reactants stored within them. When these reactants are consumed, the battery is "dead". An alternative approach would be to feed the reactants into the cell as they are required, so as to permit the cell to operate continuously. In this case the reactants can be thought of as "fuel" to drive the cell, hence the term fuel cell.
Corrosion is the deterioration of materials by chemical processes. Of these, the most important by far is electrochemical corrosion of metals, in which the oxidation process M → M+ + e– is facilitated by the presence of a suitable electron acceptor
One way of supplying this negative charge is to apply a coating of a more active metal
a very common way of protecting steel from corrosion is to coat it with a thin layer of zinc
A more sophisticated strategy is to maintain a continual negative electrical charge on a metal, so that its dissolution as positive ions is inhibited. The entire surface is forced into the cathodic condition.
Electrolysis refers to the decomposition of a substance by an electric current
2 Al2O3 + 3 C → 4 Al + 3 CO2
Nernst equation allows one unknown concentration to be determined from a measurement of the cell voltage.
aOx + ne- ↔ bRed
E = E0 – (2.3026RT/nF)log ([Red]b/[Ox]a)
E: the reduction potential at the specific concentration
n: the number of electrons
R: the gas constant (8.3143 V coul deg-1 mol -1)
T: the absolute temperature
F: the Faraday constant (96487 colul eq-1)
At 25oC, the value of 2.3026RT/F is 0.05916
Ecell= Eind - Eref
Difference in potential
(Change in potential)
Mobilities of ions
Calomel Reference Electrodes
Silver/ Silver Chloride Reference Electrodes
Used in pH meter, by using glass electrode
In environment, used to analyse ion -CN-, F-, NH3, and NO3- in water and in wastewater.
Coulometry: electrochemical method based on the quantitative oxidation or reduction of analyte
- Measure amount of analyte by measuring amount of current and time required to complete reaction
charge = current (i) x time in coulombs
Q = ite
A coulometer is a device used for measuring the quantity of electricity required to bring about a chemical change of the analyte.
It is usual practice in coulometry to substitute the ammeter
Diabetes is a serious disease and is the fourth leading cause of death by disease in US. Its causes are unknown, and there is no cure.
Testing blood: A Crucial Tool