Questions tagged [electrochemistry]

The branch of chemistry that deals with the study of redox reactions and how they can be applied to generate electricity (in electrochemical cells) and to carry out non-spontaneous reactions using electricity (electrolysis).

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200 views

Does relative amount of lithium and cobalt oxide change in recharged battery?

There is a question on my assignment about stoichiometry. I spent 2 whole days searching and review this topic but still clueless. Reaction in lithium ion battery $$ \ce{Li(s) + CoO2(s) → LiCoO2(s)} \...
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316 views

Ionize Hydrogen and Oxygen Gas in Electrolytic Cell?

As is well known, water can be electrolyzed into oxygen and hydrogen gasses. However, all redox reactions can be run in reverse. If I were to electrolyze water in 2 closed containers (in order to trap ...
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2k views

Could I settile for galvanized steel over stainless for salt corrosion resistance?

Bear with me, I'll get to the chemistry soon. I have a float tank that I want to attach a skimmer to. Unfortunately, the enclosure is weakened by cutting a hole out of the ABS plastic. The weight ...
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114 views

Double anode in simple cell

What would happen if I kept two copper plates and one zinc plate in a solution of dilute sulfuric acid, and joined two copper plates with wires? (The wires would connect to a single wire and be ...
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768 views

Why does the potential difference of a current drop, when silver nitrate is added to deionised water?

Semi-related to Why do some salt ions in solution conduct electricity better than others? After conducting more experiments, using deionised water as an analyte only, I found the potential difference ...
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Reaction of solid metals with a solution of metal ions

Explain the following experiments and their results. What is their chemical equations as well? When immersing a Magnesium (Mg) chunk inside aqueous solution of Copper ions (Cu(II)), a red-brown ...
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96 views

Galvanic Cells, theoritical voltage [closed]

This reaction proceeds in the galvanic cell: $$\ce{Zn + Pb^{2+} -> Zn^{2+} + Pb}$$ I need the equation for the half-reactions of this cell and the theoretical voltage produced by this cell if ...
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735 views

What is the meaning of electrode potential?

When we say that the electrode potential for $\ce{Co}^2$$^+$/$\ce{Co}$ is -0.28 V and $\ce{Cu}^2$$^+$/$\ce{Cu}$ +0.337 V, what is the physical meaning? Can you conceptually explain when two electrons ...
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353 views

pH Changes in primary cells

Primary Cells - pH changes during discharge Alkaline Cell: Manganese Dioxide Zinc Alkaline Cell Anode (-) $\ce {Zn(s) + 2OH^{−}(aq) → ZnO(s) + H2O(l) + 2e^{−}}$ ...
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Loading nickel metal hydride battery for the first time

I just bought a new hair clipper and I was about to start shaving my head when I noticed that it was almost at 0%. It has a nickel metal hydride battery. The manual says I have to load it for 24h ...
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Salinic bridges in voltaic cells

I'm doing a study a study on voltaic cells. I've been working with them for a while and one of the questions that I've had is how does the salt bridge affect the cell. I mean, I know it allows ions to ...
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243 views

Liquid crystal current flow

In a liquid crystal cell used for LCD the conductive substrates, usually made of ITO, are in contact with the liquid crystal. The question is: when a voltage is applied to the electrodes to reorient ...
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51 views

Does the Li-F cell possess the highest possible voltage?

My question is quite straightforward: would a theoretical cell with fluorine and lithium yield the highest possible standard potential of all? The table of Standard electrode potential in Wikipedia ...
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How the concentration of anodic half cell increases in galvanic cell?

According to my textbook Concentration of anodic half cell increases and that of cathodic half decreases when two electrodes are joined by a wire. I have also read that it is connected with a Salt ...
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37 views

Non - Polarizable Electrode/Interface

Non-polarizable electrode or interface is an electrode without charge separation on electrode/electrolyte interface or without double layer at which electrochemical reaction happens infinitely/...
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Why do we need salt bridge in a cell during potentiometric measurement as there is no or minimum redox activity at electrodes?

In electrochemical cell, we need salt bridge to maintain electrical neutrility in both halves cells during redox reaction?. But in during potentiometric measurement, no or minimum current is drawn and ...
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How can the difference between surface energy and electrostatic repulsion be calculated in electroplating?

When metals are electroplated unto surfaces, there are a myriad of forces at play. To set a clear example, if one were to electroplate a magnet with a diamagnetic metal such as bismuth, there will be ...
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27 views

In a perfect electrolytic cell, would the anode and cathode change by the same amount

If I had a theoretically perfect electrolytic cell, such as one with Copper anodes and cathodes, and a copper nitrate solution, over a given time period with a voltage applied, would the change in ...
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39 views

Potential difference between metallic electrodes in water

If I dip two pieces of metal in tap water I measure a potential difference between the two electrodes with a common digital voltmeter. For example, for Cu and Al I measured 0.55 V and for Cu and Fe I ...
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1answer
22 views

Can you create a temporary bond in between an atom and a filter by electrically charging the filter?

I want to be able to turn a filter on and off by electrically charging the filter so that it creates a temporary bond that blocks up the filter then, by discharging the filter, releasing the temporary ...
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56 views

Why do galvanic cells need a salt bridge while electrolytic cells don't?

I see the questions of why a galvanic cell needs a salt bridge and why a electrolytic cell doesn't need a salt bridge being answered separately but I still can't grasp why you are not allowed to mix ...
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19 views

How are ions transported in solid state electrolytes?

Consider an inorganic solid state electrolyte in a solid state Li-on battery. It being solid means that the atoms or ions that make up the solid itself are not mobile. Then how do the ions move ...
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34 views

How to write the Nernst Equation for this reaction?

I am required to write the Nernst equation for the following reaction: $\ce{O_2 + 4H^+ + 4e^- -> 2H_2O}$ Clearly, here $\ce{O_2}$ is getting reduced from an oxidation number of zero to an ...
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What is the reason for decomposition of layered cathode materials?

Articles like this claim oxygen can evolve from layered metal oxide cathode materials when charging the Li-ion battery. Is it the high positive potential given to the cathode while charging pulling ...
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29 views

is electrolysis of water less efficient with warm water? E.g 40, 50, 60… °C

I see there is High-temperature electrolysis which is a whole different animal than room temp electrolysis. I want to know if electrolysis of lukewarm water will behave much differently. My guess is ...
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Why a Li-ion battery, when in storage, is better kept around 85% instead of 100%?

I discovered that in my laptop settings, I can select an option that is best chosen when the laptop is mainly connected to AC power, and apparently keeps the battery at a lower SOC. I found this ...
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About the acidity of phenytoin

Can you explain why phenitoin is weak acid even though nitrogen is base? Does carbonyl group always make structure acid? If this structure doesn't have carbonyl group, would it be base not acid?
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Electrolysis in Electrophoresis of proteins and DNA

Can electrolysis happen in an electrophoresis assay (such as SDS-PAGE)? To perform electrophoresis, the substances must be dissolved in an aquatic buffer with a previously determined ionic strength. ...
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29 views

Is it possible to make a concentration cell without ion-permeable membrane?

I struggle to understand the use of ion-permeable membrane (or salt bridge). https://en.wikipedia.org/wiki/Concentration_cell If i pour two solutions with different concentration, why do you need the ...
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23 views

Effect of concentration on voltage from the perspective of energy

As I understand it, the voltage in an electrochemical cell is due to the electrons transferred having a decrease in electrical energy as they go from one species to another. I assume that this change ...
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45 views

What is the difference between these notations and terms?

I can't tell if they're being used interchangeably or if there's some nuanced difference betweem them. Here they are: $E^∘$ $E_0$ $E_h$ $E^⦵$ If I understand correctly, electrode potential is the same ...
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How to use anodic and cathodic overpotentials to calculate electrolytic energy efficiency?

I am trying to calculate the energy efficiency for $\ce{CO2}$ reduction to formate, coupled to water oxidation based on literature data. $$\ce{CO2 + 2e- + 2H+ -> HCOOH}$$ $$\ce{H2O -> 2H+ + 1/...
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What Determines the Value of Symmetry Factor (Charge Transfer Coefficient) and What is its Connection With Transition State Structure/Configuration?

I know that symmetry factor determines symmetry of energy barrier for reduction and oxidation. It is an fraction of electric potential energy difference of electron in electrochemical double layer ...
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Electorchemical Systems (Newman 3rd edition) problem solving

I am trying to solve the very first problem (Problem 1.1) of Newman 3rd edition book. The book problem goes as follows: 'Starting with the following equation for the concentration overpotential: $\...
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28 views

Why is zinc electrode at a higher potential than copper electrode in a galvanic cell?

I read somewhere that this happens because of better shielding of outer s electrons due to completely filled d orbitals of zinc, but I didn't understand it. Since Zn has an electronic configuration of ...
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26 views

Variation of battery potential with current density

It is found experimentally that the potential of an electrochemical cell with applied current density varies as follows: To produce the passage of current through a cell it is necessary to apply a ...
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67 views

What happens when solution containing two or more cations are electrolysed at an excess potential?

$\pu{250 mL}$ of a waste solution obtained from the workshop of a goldsmith contains $\pu{0.1 M}$ $\ce{AgNO3}$ and $\pu{0.1 M}$ $\ce{AuCl}$. The solution was electrolyzed at $\pu{2 V}$ by passing a ...
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How to estimate gas yield from polarization curve of the electrolyser

A good characterization of electrical properties of the alkaline water electrolysis of the water is its polarization curve. Is there a reasonable way to estimate gas yield for each point of the ...
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43 views

Weight Percent Standard State

I am having one doubt in weight percent standard state...Please see the quote(Taken from the legendary thermodynamics book by David Gaskell): If deviations from Henry's law occur below 1 wt %,then ...
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Surfactant micelles from glassware

FYI to start- I'm not a chemist by training, so assume I'm missing some basic knowledge of the field. I've been trying to do some electrodeposition with an iridium tetrachloride-based solution, and my ...
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35 views

Question about reversible chemistries in anode and cathodes

I've been reading a lot about cathode and anode chemistries recently involving Li-ion cells and solid state chemistries. What makes a decent anode seems to make sense as it is a lower potential area ...
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25 views

Do the ions of the two electrolytes mix in the salt bridge of a galvanic cell? [duplicate]

I read several times in books and on the internet that they do not, but this illustration on the Wikipedia confused me because of the zink and the sulfate ions are written above the arrow (image ...
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55 views

How does the cation radius affect the rate of increase of the electrical conductivity of a salt in aqueous solution?

Potassium chloride has a greater ionic radius than sodium chloride. How does this affect the fall in rate of increase in conductivity as concentration concentrations? I know the following factors ...
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21 views

Can I mix pressures and concentrations when finding equilibrium constant? [duplicate]

In order to find the equilibrium constant (or reaction quotient) I know I can find the value as the products over reactants raised to coefficient exponents. But, in all of the problems I have had to ...
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What does a sigmoidal and non-sigmoidal shape of a oxygen reduction reaction (ORR) voltammogram mean?

While testing materials for their ORR performance, one can encounter linear sweep voltammograms that have a well defined diffusion plateau and a good sigmoidal shape. On the other hand, the opposite ...
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34 views

Methane Sensor electrochemical reaction

When using a methane sensor a voltage is applied and much like electrolysis if the voltage is above the decomposition potential a reaction happens. Flammable gasses like methane are easily oxidized ...
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Is there a way to theoretically estimate the overpotential losses in a battery?

Me and my team are currently designing a battery and are looking to do some pre-experimental analysis of different battery chemistries based on their overpotential losses. I am aware of the Butler ...
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173 views

How to find number of moles of HNO3 behaving like acid in a redox reaction?

In the reaction $(1)$, how to find the number of moles of $\ce{HNO3}$, which is behaving like acid? The reaction is given as follows: $$\ce{Sn + HNO3 -> Sn(NO3)2 + NH4NO3 + H2O} \tag1$$ To find ...
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33 views

Conducting cyclic voltammetry in an air sensitive manner

Does anyone have suggestions on ways to conduct cyclic voltammetry on an air sensitive material without shipping the entire set up into a glovebox? This is for redox active organometallic compounds.
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128 views

How do you purify gases formed in electrolysis with a potassium hydroxide electrolyte?

I am interested in the $\ce{KOH}$ vapor that is released with my gasses during electrolysis. I have two questions. What would be the best place to start research on the $\ce{KOH}$ vapor produced in ...

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