An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). The word was coined by William Whewell at the request of the scientist Michael Faraday from two Greek words: elektron, meaning amber (from which the word electricity is derived), and hodos, a way.The electrophore, invented by Johan Wilcke, was an early version of an electrode used to study static electricity.
Am I right to think that the potential established at an electrode immediately when placed in solution is given by
E = E° - R \cdot T \cdot log_e(Q_{surface})
where the potential E of the electrode results from the standard electrode potential (E°) of the reaction and the reaction quotient...
What is the relation between Electrode Potentials and Redox reactions ?
Can we determine the relative strength of reduction of a metal by looking just at the electrode potentials ?
Here is a particular thing that confuses me :
We know that the standard electrode potential of Lithium is...
Hi
I'm new to the forum, so first I want to say hello to everyone.
I have been interested in Colloidal Silver lately, and I have produced it with electrolysis in distilled water with NaCl as an electrolyte. I have used a Silver electrode and cathode for both of these experiments.
I...
In set-up with two half-cells and a voltmeter, the potential difference is measured using the voltmeter.
But voltmeter has high resistance,which i know is still able to measure potential difference,but wouldn't it prevent electrons from flowing
What i meant was,the use of voltmeter creates a...
Homework Statement
1st question:A voltaic cell is made up of mg2+/mg half-cell and fe3+/fe2+ half-cell. Which of the following statement are correct?
a.addition of water to the fe3+/fe2+ half-cell has no effect on cell emf.
b.increasing the temperature has no effect on the cell emf...
I'm new to this forum, I am studying in grade 9 and I am working on my electrolysis project but I had trouble understanding about ion and electrode (this is not my homework, I just don't understand) why does positive ion attract to negative electrode, I know that positive should attract...
I found this article on the web, describing how metals set up electrode potential in water or solution. How I see it the whole explanation makes sense to me, but I am not sure if its the right explanation. Could someone verify this? :confused:
If I try to determine the standard electrode potential of
Fe2+ -------> Fe3+ + e-
What would be the concentrations of Fe ions ?
Would I mix 1 mol/dm3 of Fe2+ and 1 mol/dm3 of Fe3+ ions ?
I don't know why, but I just can't figure this out.
"Calculate the electrode potential for a silver filled electrode in a solution of 0.00550 M AgNO3 solution."
I got that
Ag+ + e- --> Ag(s) had an E* = .80V
I got that the answer is E=.80 - .0592 log (1/.00550M)= .6655 V
But why...
Hi,
Someone told me that a potential of 10^6 volts is not stable because it would cause spontaneous electron-positron creation from the vacuum.
Is this true?
I thought one could reach higher potentials than 1000000 volts.
I have a question on electrolysis:
In the electrolysis of aq Copper (II) Chloride using silver electrodes, what are the products?
Cathode : Copper or silver are deposited here? cos both are in the solution
anode : silver electrode decrease in size... with silver deposits?
Am I correct?
Homework Statement
Evaluate the equilibrium constant for the formation of triodide ion.
I2 + I- ------> I3-
a 298K, if EI2|I-o = 0.6197V and EI3-|I-o=0.5355V
I don't understand one thing - At equilibrium, ΔG=0 so that Eocell=0 (from the equation ΔG=-nfE) but Eocell is not zero for...
Homework Statement
If 3.00 10-3 kg of gold is deposited on the negative electrode of an electrolytic cell in a period of 2.62 h, what is the current in the cell during that period? Assume the gold ions carry one elementary unit of positive charge.
Homework Equations
delta Q/delta T...
My question about electrochemistry is best phrase via an exercise in "Intermolecular and surface forces" by Israelachvili (although this is not my homework problem!):
When an electric field is applied across an electrolyte solution containing charged particles they are seen to move parallel...
Hi, I am trying to understand what's going on in a standard three electrode system such as one used in cyclic voltammetry and the functions of each of the electrodes. I.e What role does the Working, Counter and Reference electrodes play?
The conclusions iv'e come to so far is that working...
[Moderator note: This is an old thread from 2010. But it sounds like a good question, so I moved it here and bumped it to the top.]
Hello, this is my first post to PF. I've been trying to find out my answer in similar posts (resistance of a disk, ...) with no luck. So I would really appreciate...
well i would like to know how do we label the electrode as negative and positive in a daniel cell. i dnt want the learn course like anode is this and cathode is this
but what i want to know as to what's the concept behind that labelling
my book says that if the electrode has a positive...
Homework Statement
Why are carbon, platinum and gold inert?
Homework Equations
Duplet or Octet configuration
The Attempt at a Solution
We use inert elements such as carbon, platinum and gold as the electrodes to prevent the electrodes react with the electrolyte. As far as I know...
Hi, Could someone give me some basic idea or information
1. How to measure the capacitance of interdigitated metal electrode of about 250 nm wide and 2 mm long on a silicon wafer, spacing between the electrode is 250 nm which is bonded bonded to copper pads.
2. Is it possible to measure the...
1. Can someone explain the density of the field line near the electrodes for the different electrode.
2. How would the different field densities described above affect the force on a charge?
Homework Statement
This question is my translation but there should be all info needed.
First part:
Calculate the emf and standard electrode potential of the cell Zn/ZnO/KOH(aq)/Ag2O/Ag
ZnO(s)+H2O(l)+2e- =>Zn(s)+2OH-(aq) E=-1,26V
Ag2O(s)+H2O(l)+2e- =>2Ag(s)+OH-(aq) E=0,342V...
Electrode Voltage Difference
Homework Statement
A vacuum photodiode is constructed by sealing two electrodes in a vacuum tube. The electrodes are separated by L and connected to a battery and a resistor (R). The potential difference between the cathode and anode is approximately equal to...
Homework Statement
Suggest why manganate(VII), rather than dichromate(VI) is used to titrate with Fe(II) in volumetric analysis.
The Attempt at a Solution
i have figured out 2 possible answers but both may not be correct...
1. the colour change is sharper with manganate (purple to...
Dear All
I will be grateful for any idea on how to measure electrochemically the charge carrier in an electrode say working electrode made of Al.
Thank you from advance
Shay
Dear subscribers
Re: Stability test of reference electrode
One of the important properties of reference electrode is its stability during measurements or potential scan. How one can check its stability in a certain electrochemical system?
One of the way is to use internal reference...
Consider a capacitor which is just like a plate capacitor, but instead of the upper electrode being a plate it is a point charge Q. the lower plate is held at a fixed potential V=0.
how could you calculate the capacitance of the system?
when trying to calculate - it looks like it will be 0...
Homework Statement
I've two parallel plate as in attachment. The electrode area is A, when voltage are supply to the electrode, electrostatic force will be generated.
Homework Equations
Here, I would like to find the solution or equation of the generated force in x or y direction...
Does anyone know why we prepare F- containing solutions with plastic beakers and cups instead of the regular glass beakers before measuring the responses with F- ion selective electrode
Is it because F- in corrosive?
where can i find infomation on this?
Thanks a lot~
Homework Statement
I have an op amp with two electrode inputs. Each input has 5V of common 60 Hz noise. The size of the signal I want to measure is 9 mV. Signal to noise ratio needs to be 10 to 1.
Homework Equations
I know that CMRR = 20 log (DMG/CMG), where DMG is differential mode...
Electrodes in cells usually have a sign of either + or -
My textbook talks about the + as because the electrode is positively charged and - when negatively charged. But is that correct? The electrodes are meant to be conductors and shouldn't be charged at any time. When they do, the ions...
In a battery cell, let iodine (I2) be the oxidant. In this half cell, what could the electrode be? Could it have an I2(solid) coating so when it accepts electrons, it will form iodide and fall into the solution? I recall I2 was a solid. But what physical form would iodide (I-) be? It will try to...
Hello everybody
I would like to know the potential of two electrode.
1- The first is the electrode of Ag/Ag+ in a saturated solution of NaCl
I think that the pKs of AgCL is 9.8 (is it right?)
So
E= E0+0.06log[(Ks)1/2]
E=0.8-0.506
E=0.506 vs ENH
Is it correct? (in a book I found a...
When we work out the E cell of with the electrode potential values of Zinc and copper (for example) Why does a positive E cell value indicate that the reaction is plausible?
The standard electrode potential of a Cu/Cu^2+ half-cell is given as 0.34V. However, the half-cell will only have this electrode potential relative to the hydrogen electrode when the concentration of Cu^2+ ions is 1mol.dm^-3.
But won't most of the aqueous Cu^2+ ions form complexes...
i am looking into buying either a stick electrode arc welder
or a semi-automatic flux spool fed arc welder
does anyone have suggestions about using either/or?
thanks
Hi,
I have a problem with copper electrodes. I spin-coat TPD on them and due to differences in work function of the copper(4.7eV) and TPD(5.4eV) I do not get almost any current from such a system. You can take a look at TPD here...