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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1answer
113 views

Can the direction of electron flow in a voltaic cell be reversed?

I am wondering if the direction of electron flow in a voltaic cell be reversed such that the cathode becomes the anode and vice versa. I understand this is not possible for two standard half-cells, ...
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2answers
28 views

What exactly is the 'shuttle effect' in sulfur batteries?

Ref : https://www.electropages.com/blog/2020/01/why-lithium-sulphur-batteries-are-taking-so-long-be-used-commercially Because they continually shuttle between the electrodes, they never change ...
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1answer
25 views

Nernst Equation for Lithium ion battery

For electrochemical cells we know $$ \Delta G = \Delta G^{\ominus} + RT\ln Q=- RT\ln Keq + RT\ln Q=-nFE $$ So for lithium ion batteries the reactions are Cathode $$ \ce{CoO2 + Li+ + e- <=> ...
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1answer
24 views

“Water in Salt” electrolyte [closed]

How do I prepare a water in salt electrolyte of $\ce{AlCl3 . 6 H2O}$: water = 12 by mass? Does it mean $\pu{100 ml}$ of water contains $\pu{12 g}$ of the salt since the specific gravity of water is $\...
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2answers
83 views

Copper electrode in a Daniel cell

Suppose I have a beaker containing $\ce{CuSO4}$ solution and I dip $\ce{Cu}$ rod in it. What reactions are going to take place? Is the $\ce{Cu}$ rod going to acquire any positive charge? I am asking ...
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1answer
51 views

Applied Potential and Electrochemical Cell Potential

Electrolysis of molten lithium hydroxide at $\pu{750 K}$ to form lithium metal $$\ce{4 LiOH -> 4 Li + 2 H2O + O2}.$$ Electrolysis will only proceed at an appreciable rate when the applied ...
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1answer
34 views

How the electrolyte help for oxidation and reduction process?

In a cell, There are two main parts namely : Electrode Anode Cathode Electrolyte We can take the half reaction at the Cathode. When the current flow from Anode to cathode there is a reduction ...
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2answers
58 views

How can I add more electrons to copper? [closed]

In a galvanic cell, there are two reactions taking place. One is oxidation and other one is reduction. The reduction reaction is $\ce{Cu^2+ + 2 e- -> Cu}$. In this reaction, the copper 2+ ion ...
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1answer
38 views

What is the relationship between concentration and voltage in a galvanic cell? How do you calculate the theoretical?

I am a year 12 Chemistry student and I was wondering if you could help me with some questions I have about a Galvanic cell experiment? I am doing an experimental report in Chemistry. The experiment I ...
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1answer
30 views

How can there be concentration and pressure terms simultaneously in the Nernst equation?

In the Nernst equation we are taught that the reaction quotient can have pressure terms and concentration terms simultaneously. According to my knowledge this does not happen anywhere else, so why can ...
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0answers
34 views

Charge and Discharge of a Battery [closed]

I'm a student who majors Chemical Engineering. I just have a question shown as below. First of all, I don't understand the answers of both 1) and 2). In my opinion, the answers should be switched. ...
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0answers
30 views

What is the activation energy of a Daniell cell?

I'm having trouble finding a posted literature value for the activation energy for the Daniell cell redox reaction: $$\ce{Cu^2+ + Zn -> Cu + Zn^2+}$$ Where might I be able to find this ...
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2answers
266 views

Does a zinc metal coating react with coffee in a coffee grinder?

I'm restoring an old coffee grinder and I want to give the grinder mechanism a nice zinc / silver coating. But I read it is not safe for zinc to be in contact with acidic foods. When I look at the ...
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0answers
40 views

Free electrons of the wire in a galvanic cell [closed]

In a galvanic cell, do the free electrons contained inside of the conductive wire actually flow since a voltage is created across the wire, or is it just the electrons produced by the redox reaction? ...
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1answer
20 views

Controlling Current Density in Electrowinning Cell

What are the parameters which govern the current density in an electrowinning cell? What equations relate Current Density to the applied potential difference? Is it simply just Ohm’s Law J = σE? ...
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1answer
37 views

electrochemistry experiment

something strange. i made an electrochemistry experiment in which i have measured the potential of cell: Ag, AgCl | (1M)KCl ║ [Fe(CN)6] 3-, [Fe(CN)6] 4- | Pt with different concentrations of Fe+2/Fe+...
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1answer
67 views

How can sodium be reduced in the Castner–Kellner process?

In the Castner–Kellner process, why is sodium amalgam formed instead of hydrogen gas at the cathode? If we electrolyse brine solution, then it will liberate hydrogen at cathode, not sodium, because $\...
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0answers
12 views

Why does my CA data suggest non-diffusion control but CC suggests diffusion control?

I've run chronoamperometric and chronocoulometric measurements on a ferricyanide/ferrocyanide redox couple in water and KNO3. My graph from CC appears linear which is consistent with the Cottrell ...
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3answers
723 views

Do We change sign of electrode potential when reversing an equation?

I have a cell equation as: $$\ce{2Cr^0 + 3Cd^2+ -> 2Cr^3+ + 3Cd^0}$$ I am provided the standard reduction potentials as: $$\begin{align}\ce{Cd^2+ + 2e- &-> Cd} && E= \pu{-0.4V}\...
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1answer
73 views

How does solution which electrodes are immersed in effect electrode potential?

There was this question I had to do on which went like "which all metals can we not extract using electrolysis from aq soln" the answer involved the effect of solvent on electrode potentials, can ...
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1answer
23 views

Molten lithium carbonate conductivity

Does anyone know or could make an educated guess as to the conductivity/resistivity of molten lithium carbonate? Ideally, around 750 degrees C.
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1answer
486 views

What does the osmotic pressure do in an electrolytic solution?

I have learnt that in an electrochemical cell, the osmotic pressure in the solution hinders the flow of ions from the electrode to the solution, rather some ions may accumulate on the electrode ...
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2answers
45 views

What is electrolytic protection?

My highschool textbook tells me that sacrificial protection (more technically-cathodic protection) and electrolytic protection are different. I have searched high and low for an explanation of ...
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0answers
25 views

Electrical conductivity and the limits of Kohlrausch's law

I am currently writing a lab report on electrical conductance and I realized that my partner prepared $\pu{0.1 M}$ solution instead of $\pu{0.01 M}$. Now, I am supposed to find the molar conductivity ...
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3answers
146 views

Electrochemistry conditions for voltage to increase in a galvanic cell

I understand that increasing the concentration of reactants in a galvanic cell generally causes the voltage of the cell to increase. But is that really the case always? Consider a standard cell of ...
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2answers
39 views

How can I eliminate the harmful gas produced from the heating/manipulation of galvanized steel? [closed]

When welding on steel with a galvanized coating, hexavalent chromium is yielded from the chemical reaction. This gas is something that I would like to eliminate before I begin welding, possibly with ...
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1answer
55 views

Do ions in a salt bridge come from the half cells in electrochemistry?

I understand the basics of electrochemsitry and galvanic cell, where there are half cells where either an oxidation or reduction reaction occur, and electrons moving between the wires provide the ...
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1answer
59 views

Why is the voltage produced by a voltaic cell affected by temperature as described by the Nernst Equation?

I understand why changing the concentrations of the electrolytes in a voltaic cell affects the voltage. Given a zinc-copper cell for example, if I were to increase the concentration of the zinc ...
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3answers
16k views

What is the difference between molar conductance and molar conductivity?

I'm learning (or at least trying to learn) about electrochemistry, but a major obstacle to that, is that different books I refer use different terms for the same symbols. So in a last ditch attempt to ...
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1answer
41 views

Setup for Sensing change in concentration of NaCl

I am making a sensor to sense the change in concentration of NaCl. My background is in electronics and chemistry is not my strong area. I got some screen printed electrodes, with Silver (Working ...
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1answer
29 views

Predicting directions of redox reactions [closed]

Hello! In this textbook example question, how come the chlorine reaction, which has the greatest reducing power will not react? If it has the greatest E of 1.36 V that means it has most reducing ...
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1answer
2k views

How to calculate the potential via Hess's law? Is my textbook wrong about this?

Given the two reduction half-reactions for the following fuel cell, determine the standard cell potential $E^\circ_\mathrm{cell}$, $$\ce{CH4 (g) + 2 O2 (g) + 2 OH- (aq) -> CO3^2- (aq) + 3 H2O}.$$ ...
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1answer
46 views

Why are dendrites formed during dilute CuSO4 electrolysis black?

During the weekend, I wanted to conduct a kid's experiment - the copper dendrite formation. I was (partially) successful and now I would like to know what went wrong. The procedure was taken from the ...
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1answer
27 views

Reduce potential by adding NaOH. With solubility

Ff I don’t know how to calculate c part.. What I did is: E=E* - RT/nF lnQ Ks(cuoh2) = [cu][oh]^2 So we can know how much concentration of cu has to be eliminated and with that we can calculate the ...
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2answers
1k views

Nernst equation for a fuel cell when gases are stored separately

I have run some tests with a PEM fuel cell and the voltage we have found was $1.44\ \mathrm{V}$. Given that the standard potential for a fuel cell is $1.229\ \mathrm{V}$ what is causing the difference ...
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1answer
43 views

How does Fe2+ become Fe in sacrificial protection? [closed]

I've searched low and high on the internet, but nothing to help me. I know that zinc is oxidised in preference to iron, and that it "donates" those two electrons to iron. $$\ce{Zn -> Zn^2+ + 2e-}$$...
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1answer
26 views

Electrochemistry - Understanding Diffusion Potential

I have a big problem trying to wrap my head around this for several hours and I cannot seem to make sense of it. I have to link this scheme with the 3 colored potential profiles on the bottom of the ...
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0answers
25 views

Why does changing the salt of the salt bridge effect the voltage produced in a galvanic cell?

My experiments results showed that the voltage decreases down $\pu{Group 1}$: $\ce{Cl-}$ salts in the salt bridge. All other variables were kept constant. $\ce{Zn}$ and $\ce{Cu}$ rods were used. ...
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1answer
126 views

Why does magnesium deposit during electrolysis of a molten mixture of MgI2 and AlBr3?

During the electrolysis of mixed salts, I read, and was taught, that the cation with a higher ionization energy would deposit at the cathode. I was also told that you cannot use the standard electrode ...
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1answer
43 views

Find pH and Kw for water with given values of conductivity

At $\pu{25 ^\circ C}$, $\lambda_\infty (\ce{H+}) = \pu{3.5 \times 10^{-2} S m2 mol-1}$ and $\lambda_\infty (\ce{OH-}) = \pu{2 \times 10^{-2} S m2 mol-1}$. Determine $\mathrm{pH}$ and $K_\mathrm{w}$. ...
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2answers
95 views

Is anode actually ever negative?

Disclaimer: This question comes from a physics student. I was studying electrostatics and I was wondering how to charge a conductor at home without any fancy furs etc. So an idea came to me: take a ...
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0answers
37 views

Galvanic Cell Temperature Dependence

I'm currently studying the temperature dependence of the following cell: $\ce{Cu_{(s)} + 2Ag^{+}_{(aq)} <=> 2Ag_{(s)} + Cu^{2+}_{(aq)}}$ ($E^⦵ = \pu{+0.46 V}$) Experimentally, I recorded the ...
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0answers
30 views

What is the yellow compound formed in electrolysis of brine?

Last week, I tried to conduct electrolysis of brine in my house using copper electrodes and 6V battery. After sometime, the entire solution turned orange/yellow. The yellow substance formed a kind of ...
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3answers
224 views

Is it possible to generate electricity by using two inert electrodes in a galvanic cell?

The Daniell cell has two active electrodes, meaning that both the copper and the zink electrodes participate in the redox reaction. However, in a lemon battery for example, the copper electrode is ...
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1answer
27 views

Is the thermodynamic stability against reduction/oxidation of an electrolyte dependent on the electrode material?

Consider an electrochemical cell with an inert Pt working electrode (WE) and some electrolyte that irreversibly decomposes upon oxidation. A minimum potential $E_{min}$ (vs. some reference) needs to ...
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1answer
22 views

How are cells rechargable?

I have learnt that you can test if a reaction is thermodynamically feasible by testing if the cell voltage $E_\mathrm{cell}$ is greater than $0$. Surely, if a reaction is feasible, then the $E_\mathrm{...
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1answer
853 views

In a galvanic cell, why does an electrode with a higher potential “pull” the electrons from the electrode with a lower potential?

I'm doing Grade 12 Chemistry and I'm unsure of this, taking the hydrogen electorde as having a potential of 0 volts. I'll use the copper-zinc cell as an example. Just let me know if I've got the full ...
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1answer
169 views

How do you calculate a half cell potential Copper(II) and Copper Sulfate?

I have to complete an experiment for school where I have copper and zinc electrodes placed into an electrolyte of copper sulfate and I have measured the potential across it at varying temperatures. ...
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2answers
42 views

Confusion regarding the positively charged copper electrode in a Daniell cell [closed]

Suppose I bought a newly manufactured Daniell cell then in this situation, can someone explain what all will be going on at the zinc and copper electrode? (Since it is newly manufactured and not used ...
3
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1answer
42 views

Can I anodize an aluminum coating on steel to have better corrosion inhibition for the steel?

I am planning to coat aluminum on steel and I want to give the steel its maximum corrosion protection. Is anodizing the coating necessary?

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