Electrode Definition and 81 Threads

Item (a) of problem 1 of a chapter on "Galvanic Cells" asks us to calculate the Standard Gibbs free energy for this cell reaction. I can do the calculation, but I am frustrated by the following. The entire chapter focused on the electrochemical cell...

I am trying to understand batteries and their electrochemical behavior Consider a cell composed of two half cells where each half cell contains an electrode in an electrolyte solution. Different electrode materials have different tendencies to acquire or lose electrons. when the electrodes...

Hello, I wanted to know if connecting a battery in series with a voltaic cell would increase the rate of the redox reactions. Let's take the simplest example of a voltaic cell constituted by a Zn/Zn2+ half-cell connected to a Cu/Cu2+ half-cell. When the circuit is closed, the Zn electrode will...

Hi I am looking to find the equation that determines the minimum (and if possible maximum that might damage the electrode) voltage that starts the electrolysis process for a given area of a graphite electrode in a brine solution medium (lets say 30%) at equilibrium state. Also how does the...

Iris electrode The potential distribution in the vicinity of the iris electrode, denoted by ##V(r,z)## is rotationally symmetric. After some derivations, the author arrives at the following two equations: $$\begin{align} E_z &= - V'_0(z)\\ E_r &= \frac{1}{2}V''_0(z)r, \end{align}$$ where...

Hey guys, I have two questions: 1) I thought absolute electrode potential is galvani potential difference at the interface. However, it is given by this equation in John Bockris - Modern Electrochemistry: $$ E(abs) = ^M\Delta^S\phi - \mu_e^M/F $$ First term is galvani potential difference on...

Voltmeter is an instrument which measures electric potential difference between two points. When measuring electrode potential of some redox system (vs SHE for example), it is said that voltmeter reading contains sum of all potential differences present in a cell. This includes all...

Hello Inspired by this video, I wondered if it was possible to create a process of electrolysis in saltwater using a single electrode. To my understanding (Please see the attached diagram), if a direct current passes through I2 (after the diode) a direct current must also pass through I1...

Hi, I am interested in designing an electrode that reduces the peak e-field intensity at the edges of the electrode. I've read some papers and it looks like there are quite a few. I'm not really familiar with the terms, so I decided to start off with what looks like is one of the simpler ones...

Recently I've been researching parallel plate capacitors and was wondering what effects the material had on the charge capacity of the plate. I found one source for measuring the capacity based on its material, but haven't seen any textbook evidence to support it yet. Any feedback on the...

Consider the cell ##Pt | H_2 | H^+ || Ag^+ | Ag##. I’ve sketched the electric potential against distance across the cell: I would think the electrode potential of the ##Ag+/Ag## electrode is ##V_{Ag+/Ag} - V_{H^+/H_2}##, which I’ve labelled on the right. We set ##V_{H^+/H_2} = 0## as per...

My teacher insists that the reverse reaction has a negated electrode potential (oxidation potential?). This doesn’t make sense to me, since I am under the impression that the electrode potential is a property of the half cell at equilibrium and not of either of the reactions in a particular...

Do following half-reactions have electrode potential that depends on pH? I know H+ or OH- ions wouldn't be included in Nernst equation for these, but would pH affect chemical balance in these reactions, and therefore electrode potentials? Br2+2e- -> 2Br- Cl2+2e- -> 2Cl- I2+2e- -> 2I- S2O8+2e-...

I know how to find the electric field of more traditional designs i.e. a sphere, through Gauss' Law but I don't think Gauss' Law applies to this scenario. I tried to separate each part of the electrode into simple spheres and rods and using Gauss' Law to find these individual elements. This...

The common mantra is that when measuring conductivity in solutions the electrodes will build up a polarization layer and disturb the measurement, thus a 4 electrode measurement is used and an alternating current impressed up on the outer electrodes, usually around 1000 hz. I have been trying to...

Hello all. I am conducting a simple research project, and am having a little trouble with the math for paschen's law. my question is. At 74762 Microns of pressure, using pure Neon gas, what is the electrode spacing in mm for the minimum breakdown voltage of that gas? Thank you.

I have obtained an experimental setup of a Marx bank which has electrolytic liquid resistors. In the tubing of the resistors are various strength solutions of copper sulfate. I was told that the electrodes are copper but there appears to be some sort of plating or other reaction occurring...

Help! I was under the assumption that a gold electrode for oxygen would be able to sustain water electrolysis with sodium bicarbonate as the electrolyte without degrading, so I bought a foot long of 28 gauge 24k(pure gold) wire, but I've been putting it to the test for about 30 minutes and it's...

Here is the Wikipedia page on electrode potentials. Here's how I'm reading it, which makes no sense: If a singly ionized atom of strontium donates an electron to the hydrogen in the standard hydrogen electrode, this will emit 4.101 eV of heat (395.68 kJ/mol). If cesium is used, there will be...

I am not an electrochemist, but I do need to understand various issues with an analytical chemistry instrument. This is a somewhat open-ended question. The instrument applies a voltage waveform across two palladium electrodes. Typical waveform is 2 Hz, 4 Vpk sinusoid, for brief intervals...

I am doing nerve conduction research for the Intel International Science Fair and I need to make a stimulating electrode or just something that I can make with common items and that can release enough voltage to stimulate/activate the nerve. I made one using a lighter, but I am not sure that it...

an idea for my new project construction - a cubical bowl of tap water , 2 sheet electrodes for 1 pair (y-axis pair)of opposite face(square wave 10Hz 10vpp), 2 sheet electrodes for the other pair (x-axis pair)(similar square wave lags by half cycle ) left hand touches adc pin. right hand touches...

Probably the title wasn't really clear. What I am asking for is an explanation. Isn't the potential of the electrode is created by a combination of ions and electrons? and we can't possibly measure the absolute potential. However, we can measure it relative to other electrodes such as hydrogen...

Homework Statement Homework EquationsThe Attempt at a Solution From the calculation of the potential of the cell and the potential for the copper electrode, it states that the hydrogen electrode has a potential of -0.09 V. But I thought hydrogen electrode is standard so it should be zero...

Will the high surface area of carbon nanotubes and high dielectric constant of calcium copper titanate be used together in supercapacitors?

Hi there, I have a question that I think has an answer but I cannot find it in the literature in any convincing way: I am using two models, WKB based and TMM based to calculate the transmission probability of electrons through a (initially rectangular) thin potential of the order of 1-2nm...

Hi, I'm stuck on part b) of the question below: Q: In order to perform pH determinations with a glass electrode, the cell potential was measured for threestandard solutions with the following pH values at 25 C: 2.04, 7.05, and 9.20. The cell voltage readout(in mV) for each of the above solutions...

For an electrolytic cell, the voltage source Vs, does not contribute directly to the potential on the electrolytic electrodes. Vs determines the current and can add charges to the electrodes. This can be observed when charging supercapacitors and is discussed in these threads ...

I've been trying to build a closed system water electrolyser with easily available materials which allows me to collect the gases separately. To do so, I've been meaning to build an acrylic housing with a textile separator in the middle of two compartments which houses the anode and cathode. The...

What effect (if any) would changing the surface area of electrodes in a lithium ion battery have? Would it allow for faster battery charging? Faster discharge rate? Thanks in advance

I built a Hoffman apparatus with graphite electrodes. I hooked it up to a make shift power supply from an xbox powerblock. It was filled with battery acid for the electrolyte. Now, the graphite electrode is 99% graphite rod. For some reason the graphite electrode on the negative(black)...

In our textbook it is written that -voltmeter measures the electrode potential difference between 2 half cells (in an electrochemical cell) (electrode potential refers to the potential difference between electrode and its salt solution in which it is dipped) it should come-voltmeter measures...

Why is the central electrode in a Geiger-Muller tube always positive (and not negative)? Many thanks!

When a metal (electrode) is in contact with water, an equilibrium forms: Mg ⇔Mg2++e- Adding more of the metal Mg should convert some of it into more electrons so that the ratio of Mg to Mg2+ remains the same (as the equilibrium requires). Therefore twice the amount of metal in contact with water...

Hi All, I'm working on a research project that requires putting an electrode array with 4 elements into a flexible tube filled with conductive liquid. The electrode array is a series of balls, with the first being positive and the last being negative. The idea is to measure the change in...

Reduction half reaction : Cu2++2e- -> Cu(s) I have a doubt in using the reference electrode. For example if I have the calomel electrode (ESCE=0.24V) how do I use it with the copper half cell? Are these reactions correct? Cu2++2e- -> Cu(s) 2Hg+2Cl -> Hg2Cl2+2e- To get Ecell=0.24+ECu|Cu2+

Today I was studying Atkins physical chemistry basics and I saw a bit of incoherence. ΔrG°=ΔrH°-TΔrS° ΔrG°=ΔfG°(products) - ΔfG°(substrates) ΔrG°=nFE° Data: ... ΔfH° ... ΔfG°...ΔS°(J*K*mol-1) H2(g)...0......0......130,684 H+......0.....0.....0 2H+(aq) 2e- => H2(g) Using second and third...

Does anybody understand the fundamentals of what is happening in this circuit? Tungsten welding info is all about high current... but this is a low current scenario. AC input, CDI Coil generated 20Kv (estimated) suffers voltage drop over 100mm of tungsten rod. The larger the diameter... the...

I don't understant how the positive electrode can attract both electrons and the positive Li ions as they both flow to it. Also, the way to start the whole process is to let the electrons flow, right? (Close the circuit.) Without it, the ions also don't want to start flowing, although there is...

Homework Statement Find the electric field everywhere for the following permanently polarized structures which do not support any free charge: (b) Permanently polarized slab P_0 i_x of thickness b placed between parallel plate electrodes in free space at potential difference V_0...

So I'm pretty sure this falls into both the realms of physics and electrochemistry. How would I calculate the rate of erosion of an electrode if it were sustaining an arc in a gas?

>According to http://www.chemguide.co.uk/physical/redoxeqia/introduction.html each electrode has an absolute electrode potential which is the difference between the positiveness and negativeness. So if we had a Zn plate in water and it has a negative charge of -5 on the metal. Would the absolute...

My book says smaller the electrode gap,greater the chances of a misfire. The reason stated is that this is because of a smaller activated volume. I understand the meaning of misfire: it is when electricity takes a different path due to electrically conductive residue lying between electrode...

I need to collect data via measuring EMG signals in the upper arm. I have standard AgCl stick-on ECG electrodes. My question is, if I can use normal alligator clip cables for collecting this signal from the electrode and feed it into an instru-amp? Will this affect the signal strength and/or...

This is more electrical engineering than chemistry I would think. If the current density required is 200mA per cm^2, and the electrode is a hollow copper tube that is submersed in an electrolyte in which the inside of the tube is not touching any solution, should the current be calculated...

In Standard Hydrogen Electrode why only Platinum electrode should be used and why should it be dipped in HCl?why can't we use any other metal dipped in any other acid other than HCl?

Homework Statement This isn't homework or coursework as such, but i thought it may be the best place to ask this question. The last time i posted in the other section it was deleted! Im considering the case of an electrode of finite width L in the x direction. The y direction is...

Homework Statement For some work I am doing I wish to be able to define the potential distribution as a function of the radius (ρ) between two concentric electrodes. Homework Equations One solution (from reliable literature) defines the varying radial potential as: V(ρ)=2V0(ρ0/ρ...

If I was to electrolyse a hot sodium chloride solution I'm pretty sure a copper electrode would react to make copper chloride. Whereas I would have used graphite electrodes if the solution was cold, this reaction should produce sodium chlorate which can obviously be quite reactive with organic...

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...