This document provides an overview of key concepts in electrochemistry, including:
- Galvanic cells use spontaneous chemical reactions to generate electrical energy, while electrolytic cells use an applied voltage to drive nonspontaneous reactions.
- Cell potentials and the Nernst equation relate the standard cell potential to non-standard state potentials based on reaction quotients.
- Faraday's law of electrolysis states that the amount of product formed is proportional to the quantity of electricity passed, as measured by coulombs of charge.
- Standard reduction potentials and Gibbs free energy can be used to determine cell potentials and predict spontaneity of redox reactions.
Untuk studi berbagai jenis korosi, antara lain : Korosi merata (Uniform Corrosion), Korosi Galvani (Galvanic Corrosion), Korosi Celah (Crevice Corrosion),
Korosi Retak Tegang (Stress Corrosion Cracking),Korosi Intergranular (Intergranular Corrosion), Korosi Erosi (Erossion Corrosion), Korosi Sumuran (Pitting Corrosion) dan Selective Leaching. Dan juga upaya
pencegahan korosi antara lain : coating, proteksi katodik dan Corrosion Inhibitor
Stoikiometri: Hubungan kuantitatif massa zat dlm reaksi kimia
Energetika kimia: Mempelajari energi dari Reaksi kimia
Termodinamika: cabang fisika yg mempejari hubungan antara kalor dan energi lain
Energi bukan benda yg dapat ditimbang, tetapi kemampuan yg dimilki setiap benda, kemampuan untuk melakukan kerja
Dua jenis dinding sistem:
1. Diatermal (tembus energi), &
2. Adiatermal (tidak tembus energi)
Kesetimbangan mekanik: terjadi bila sistem tdk mempunyai energi mekanik. Cth. Tekanan dalam pompa sama dengan tekanan udara luar
Kesetimbangan termal: energi yg masuk & keluar sistem sama jumlahnya
Kesetimbangan listrik: postensial listrik sistem sama dengan potensial listrik lingkungan.
Untuk studi berbagai jenis korosi, antara lain : Korosi merata (Uniform Corrosion), Korosi Galvani (Galvanic Corrosion), Korosi Celah (Crevice Corrosion),
Korosi Retak Tegang (Stress Corrosion Cracking),Korosi Intergranular (Intergranular Corrosion), Korosi Erosi (Erossion Corrosion), Korosi Sumuran (Pitting Corrosion) dan Selective Leaching. Dan juga upaya
pencegahan korosi antara lain : coating, proteksi katodik dan Corrosion Inhibitor
Stoikiometri: Hubungan kuantitatif massa zat dlm reaksi kimia
Energetika kimia: Mempelajari energi dari Reaksi kimia
Termodinamika: cabang fisika yg mempejari hubungan antara kalor dan energi lain
Energi bukan benda yg dapat ditimbang, tetapi kemampuan yg dimilki setiap benda, kemampuan untuk melakukan kerja
Dua jenis dinding sistem:
1. Diatermal (tembus energi), &
2. Adiatermal (tidak tembus energi)
Kesetimbangan mekanik: terjadi bila sistem tdk mempunyai energi mekanik. Cth. Tekanan dalam pompa sama dengan tekanan udara luar
Kesetimbangan termal: energi yg masuk & keluar sistem sama jumlahnya
Kesetimbangan listrik: postensial listrik sistem sama dengan potensial listrik lingkungan.
To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.To develop a premier world class education centre, for creating global project management professionals, thereby making Larsen & Toubro (L&T) a centre of excellence in project management.
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.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
1. JF Basic Chemistry Tutorial :
Electrochemistry
Electrochemistry
• Galvanic cells
• Cell Potentials and Standard cell potentials
• Electrolytic cells
• Faraday’s Law of Electrolysis
http://webct.tcd.ie
plunkes@tcd.ie
2. e-
Cathode
e.g. Copper electrode
Anode
e.g. Zinc electrode Salt Bridge
Electrolyte, e.g.
ZnSO4
Electrolyte, e.g.
CuSO4
-
+
Galvanic cells (also called Voltaic cells)
• use spontaneous chemical reactions to generate electrical
energy in the form of an electrical current ΔG < 0
• Made up of two half cells
• Oxidation (loss of electrons) occurs at the negative anode
• Reduction (gain of electrons) occurs at the postive cathode
• Salt bridge acts to complete the circuit by joining the two half cells
together
Most batteries are made
from Voltaic cells!
3. For the example above, the reactions occuring are:
Anode: Zn(s) Zn2+
(aq) + 2e-
Cell potentials
The electrical energy generated by the spontaneous reaction is
proportional to the cell potential.
The standard cell potential (the cell potential measured when all the
species are in their standard states) is given by:
E°cell = E°cathode - E°anode
Cathode: Cu2+
(aq) + 2e- Cu(s)
The shorthand notation for this cell is:
Zn(s) | Zn2+
(aq) || Cu2+
(aq) | Cu(s)
The cell potential, E, is a measure of how well a cell reaction can push
and pull electrons through a circuit
4. • Reduction occurs at the electrode with higher potential and oxidation
occurs at the electrode with the lower potential
• Unit of potential is the volt (V) and unit of charge is the Couloumb (C)
These are related by: 1V = 1J/C
• The charge of one mole of electrons is given by the Faraday constant,
F (F = 96,500 C mol-1)
• The more negative the reduction potential is, the more readily the
element acts as a reducing agent, i.e. is itself oxidised
We can combine the standard cell potential and Faradays constant to
give us an equation for ΔG°
ΔG° = -n F E°cell
where ΔG° is the change in Gibbs Free Energy
n is the number of moles of electrons
F is Faradays constant
E°cell is the standard cell potential
5. Have relationship between Gibbs Free Energy and Equilibrium constant:
ΔG° = - RT lnK
ΔG for a reaction depends on the concentration by:
ΔG = ΔG° + RT ln Q where Q is the reaction quotient = [product]
[reactant]
But ΔG = -n F Ecell and ΔG° = - n F E°cell
Dividing across by nF gives: Ecell = E°cell – RT ln Q
nF Nernst Equation
-nFEcell = -nFE°cell + RT ln Q
i.e. the cell potential at any conditions depends on the potential under
standard state conditions and a term for the potential at nonstandard-
state conditions
6. Question
Which of the following statements relating to electrochemistry are
correct?
(i) Oxidation involves the loss of electrons
(ii) Reduction involves the gain of electrons
(iii) Galvanic cells use electricity to produce chemicals
(iv) The anode in a Galvanic cell is positive
(v) Oxidation always occurs at the cathode
Answer: (i) and (ii)
The standard potential of the Ag+/Ag electrode is +0.80 V and the
standard potential of the cell Fe(s)|Fe2+
(aq)||Ag+
(aq)|Ag(s) is +1.24 V.
What is the standard potential of the Fe2+/Fe electrode?
Question
Half reactions Fe Fe2+ + 2e-
Ag+ + e- Ag
Oxidation reaction - Anode
Reduction reaction - Cathode
E˚cell = Ecathode - Eanode
Eanode = Ecathode - E˚cell
Eanode = 0.80 V – 1.24 V
Eanode = -0.44 V
7. Question
If the standard cell potential at 298 K is 1.10 V for the following
reaction Zn(s) + Cu2+
(aq) Zn2+
(aq) + Cu(s), then what is the change in
Gibbs Free Energy?
ΔG° = -n F E°cell
n = no of moles of electrons = 2
F = Faradays constant = 96,500 C/mol
E°cell = 1.10 V = 1.10 J/C
ΔG° = - (2) (96500 C/mol) (1.10 J/C)
= - 212300 J/mol
= - 212.3 kJ/mol
Half reactions: Zn Zn2+ + 2e-
Cu2+ + 2e- Cu
8. The equilibrium constant for the reaction
Ni(s) + Hg2Cl2(s) 2Hg(l) + 2Cl-
(aq) + Ni2+
(aq)
is 1.8 × 1019 at 298K. What is the value of the standard cell potential
E°cell for this reaction?
ΔG° = -RT ln K
= - (8.314 J K-1 mol-1) (298 K) ln (1.8 ×
1019)
= - 109847.8 J mol-1
= - 1.098 × 105 J mol-1
ΔG° = -n F E°cell
E°cell = -ΔG°
n F
= -(-1.098 × 105 J mol-1) = 0.57 J/C = 0.57 V
(2 mol) (96500 C)
Question
9. Na+
Cl-
Anode
e.g. inert Ti
Cathode
e.g. inert Ti
Electrolyte, e.g.
NaCl
+ -
Power
Supply
Electrolytic cells
• Use an applied voltage to carry out a nonspontaneous
chemical reaction ΔG > 0
• Electric current supplied by an external source
• External source must provide a greater potential than that for the
spontaneous reverse reaction
• Electrolysis = process in which electrical energy is used to cause a
non-spontaneous chemical reaction to occur
11. Current + Time Charge
Faradays
constant
Moles of electrons
Moles product
Molar mass
Mass product
Using Faradays Law!
Faraday’s Law of Electrolysis: the quantity (moles) of product formed
by an electric current is stoichiometrically equivalent to the amount
(moles) of electrons supplied
12. Question
If 306C of charge is passed through a solution of Cu(NO3)2 during an
electrolysis experiment, what is the number of moles of copper metal
deposited at the cathode?
Cu(NO3)2 Cu2+ + 2NO3
- Cu Cu2+ + 2e-
2 moles of electrons required to reduce 1 mol Cu2+
No of moles e- =
charge
Faradays constant
= 306 C
96500 C/mol
= 0.00317 moles of electrons
From reaction stoichiometry, 2 moles electrons ≡ 1 mole Cu
0.00158 moles Cu deposited
Question
If 612 C of charge is passed through a solution of Cu(NO3)2(aq),
calculate the number of moles of copper metal deposited.
Answer = 0.00317 mol
13. How long will it take to deposit 0.00235 mol of metallic gold by
electrolysis of KAuCl4(aq) using a current of 0.214A?
Charge = current × time
KAuCl4(aq) Au(s) Au3+ + 3e- Au
For every 1 mol Au produced, 3 mol electrons required
For 0.00235 mol Au need 0.00705 mol electrons
No of moles electrons =
Faradays constant
Charge
Question
Charge = moles electrons × Faradays constant
= 0.00705 mol × 96500 C/mol
= 680 C
Time = Charge/Current
= 680 C / 0.214 A 1C = 1As
= 680 As / 0.214 A
= 3179 s
= 53 mins
14. Question
How long will it take to deposit 0.0047 mol of gold by electrolysis of
KAuCl4 using a constant current of 0.214 A?
Answer: 106 minutes
Question
How much Ca will be produced in an electrolytic cell of molten CaCl2 if
a current of 0.452 A is passed through the cell for 1.5 hours?
Answer: 0.5 g Ca
