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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4
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2answers
157 views

Can the thermodynamic predictions of redox reactions based on E and dG contradict each other?

I am referring to the following three reactions. Two of these reactions are imaginary ($\ce{M}$ and $\ce{X}$ are imaginary). $$\begin{alignat}{3} \ce{X- + 2e- \;&<=> X^3-} \qquad &&...
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1answer
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Conductivity and Molar Conductivity of Equimolar Solutions of LiCl and KCl

If one took equimolar solutions of $\ce{Li}$ and $\ce{K}$, which would have higher conductivity? Is it the same for molar conductivity? Say, $\ce{LiCl}$ and $\ce{KCl}$, of a litre each. Also, as ...
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1answer
13k views

How to find the band gap for a compound?

I have processed a si/polymer hybrid using a silane coupling agent which I need to determine the energy gap / band gap. Would you please let me know the procedure to go about determining the band gap?...
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Does Fluoroborate gets used up in Electroplating

I've been working on Tin electroplating on the side for a while now. I've formulated a mix from my usual electroplating formula template. The mix stubbornly keeps on having the Tin ions form Tin ...
2
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2answers
5k views

Electrochemical cell polarity and electrodes

In an electrochemical cell, the anode undergoes oxidation and the cathode undergoes reduction. This means that the anode loses electrons while the cathode gains electrons. However, the anode is ...
23
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1answer
5k views

Could milk rust a steel teaspoon?

Recently, while cleaning a neighbour's fridge (turned off for a few weeks), I came across a cup (closed with a lid). Inside the cup was, to my olfactory horror, congealed milk, with a steel (iron) ...
16
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1answer
1k views

Why would 1kW power supplies fail around Nitric acid (HNO3) gas?

I experienced a situation where some electrical power supplies (rated over 1kW) were exposed to nitric acid ($\mathrm{HNO_3}$) fumes at roughly 9ppm for half a day; these power supplies intermittently ...
3
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2answers
926 views

Why is current non-zero when applied potential is still below E$^0$ in cyclic voltammetry?

In this diagram (Evans et al., J. Chem. Edu.) the current is non-zero, but the potential is still below the normal potential. How can the compound become oxidized at the working electrode, when the ...
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1answer
272 views

How do I write many cyclic voltammetry curves in Nova?

We are making an electrochemical research on supercapacitors that involves checking stability of our material. That requires repeated writing of cyclic voltammetry curves. Our goal is to write at ...
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0answers
138 views

Height of potential barrier

Could anyone please help to find the height of the potential barrier between silver and copper or $\ce{Ag-Cu}$. I am working on a piezo-resistive sensor based on copper fabric and silver electrodes. I ...
3
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1answer
278 views

Electroplating metal inside polymer foam with acetone

In my research we have a method of making polymer open-cell foams with high tortuosity and pore sizes on the order of 50–200 nanometers. I can make thicknesses of 100 µm to 2 mm thick (and up to 5 ...
3
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1answer
60 views

Reactions involved in Titanium Anodisation

I am writing up a lab report investigating titanium anodisation and producing oxide layers. After some searching, all I can find is the reaction $\ce{Ti + O2 \to TiO2}$, which I am having no trouble ...
4
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1answer
132 views

How to prove that reaction is possible [closed]

I have been given task to write possible reaction equations, determine oxidizer, reducer, write corresponding electron-equations and calculate electromotive force (I do not know if that is what you ...
4
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1answer
849 views

Extraction of hydrogen and oxygen from water

The apparatus that I am using is a glass container, with two electrodes,two glass cylinders, water, and a battery. In the glass container will be filled with water and two electrodes kept inside the ...
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1answer
6k views

What is the standard potential of carbon?

What's the value of standard potential of carbon? The hydrogen and Carbon are in the electrochemical series despite being non metals hydrogen has zero potential difference what about carbon?
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1answer
693 views

Bandgap of a semiconductor for photocatalytic water splitting

I'm reading a review article on photocatalytic water splitting (using semiconductors) and I came across the following: "To achieve photocatalytic water splitting using a single photocatalyst, the ...
7
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1answer
466 views

Does phosphoric acid remove stainless steel electropolished layer?

Electropolished stainless steel has a high corrosion resistance due to the oxide film that is created during electropolishing. The film mainly consist of chromium(III) oxide. Phosphoric acid is ...
3
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1answer
186 views

Electrochromic Materials, electrode setup

I've read a lot about electrochromism. This article on electrochromic materials has also been additionally helpful. I was wondering, for these electrochromic materials, can you simply attach a small ...
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1answer
1k views

Why does the anode solution contain Sn2+ in a Sn-Cu voltaic cell?

Suppose you have the following voltaic cell: $\ce{Sn_{(s)}|Sn^{2+}_{(aq, 1.0 M)}||Cu^{2+}_{(aq, 1.0 M)}|Cu_{(s)}}$ and the salt bridge is $\ce{KNO_3}$. What I don't understand is why you need to have $...
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2answers
782 views

How do I setup the electrodes for cyclic voltammetry on a capacitor made on dry copper sheets?

I'm trying to measure capacitance of a cell I'm creating. It's composed of two copper-sheets with nano-material coated on one side, sandwiched with a membrane and wetted with $\ce{KOH}$. All of the ...
2
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1answer
31 views

Cathode region in corrosion

The anode region is on the iron where the following reaction occurs: $$\ce{Fe(s) -> Fe^2+(aq) + 2e-}$$ and at the cathode region, the following reaction occurs $$\ce{O2(g) + 4H+(aq) + 4e- -> ...
4
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1answer
146 views

How to identify which of two given electrodes with corresponding solutions is reducing more?

For the sake of the question, let’s assume that you are provided with two labelled rods of the pure metals $\ce{A}$ and $\ce{B}$ and two unlabelled bottles containing $1.0\ \mathrm{mol\ dm^{-3}}$ ...
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1answer
673 views

Iodometric titration of copper – standard electrode potentials

Upon inspection of the standard electrode potentials for the half reactions for both $\ce{Cu^2+}$/$\ce{Cu+}$ and $\ce{I2}$/$\ce{2I-}$, it becomes apparent it should be the iodide ions that act as the ...
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1answer
373 views

Is this product description wrong and a simple battery and not a fuel cell?

I won this "toy" at a science fair... Now I have to make a short presentation about it in school. On the package description they describe its energy source as "fuel cell"... It consists out of a ...
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2answers
194 views

How to separate a 5 atom thick layer of Cu from Au

I've become very curious about (electrochemical) atomic layer deposition (ALD) via surface limited redox replacement. Since the technique allows for deposition of metals in atom thick layers it's ...
4
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1answer
310 views

Intuitive understanding of standard electrode potential

I have read many books on standard electrode potential and they define the term in various ways but I just can’t seem to get an intuitive idea of it. $$\ce{Cu^2+ + 2e- <=> Cu}$$ Standard ...
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3answers
20k views

Why the salts in a salt bridge?

Take the example of a copper and zinc galvanic cell, connected by a salt bridge of $\ce{KNO3}$. I understand how the reactions will result in positive and negative charges, and that the ions of the ...
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0answers
263 views

Reduction of vanadyl ion

I want to reduce vanadyl to vanadium (III), can somebody please suggest some appropriate methods for it? I am trying to make a redox flow battery for a project but I have only vanadyl sulfate.
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1answer
292 views

How does the MG811 sensor work?

The MG811 is an electrochemical sensor that measures $\ce{CO2}$. I think is something like a redox reaction but i don't understant how it produces $\ce{e-}$ so i can read them and get the $\ce{CO2}$ ...
6
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1answer
176 views

galvanic corrosion in the wild: where is the reduction?

Galvanic corrosion occurs of an active metal (i.e. iron or zinc) in contact with a passive metal (i.e. copper) in a conductive solution. A famous example is the corrosion of iron girders in contact ...
4
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1answer
75 views

If given a half reaction, how do you determine if an element can exist in a acidic conditions?

I was given the formulas, $$\begin{alignat}{2} \ce{MnO4^2- \;&<=> MnO4- + e-}\quad &&E^\circ = -0.56\ \mathrm{V}\\ \ce{MnO2 + 2H2O \;&<=> MnO4^2- + 4H+ + 2e-}\quad &&...
4
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1answer
74 views

Respect to other chemicals in reduction/oxidation potentials

From what I understand, the standard reduction/oxidation potential table is based on the hydrogen half reaction which makes a reduction and oxidation potential of 0 respectfully. In a research ...
6
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1answer
897 views

Corrosion of a galvanic couple made with silver and gold

If a bangle is made out of gold and silver, connected with each-other would there be corrosion happening? If so, can it be explained using the galvanic series? Also do those metals undergo oxidation ...
2
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1answer
1k views

Balancing reduction equations for galvanic cell

Problem: Compute the potential of the following galvanic cell: $$(\ce{Mg (s)} \mid \ce{Mg^2+ (aq)}\ (0.30\ \mathrm{M}) \mid \mid \ce{Sn(OH)4^2- (aq)}\ (0.10\ \mathrm{M}); \mathrm{pH} = 9 \mid \ce{Sn (...
6
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1answer
276 views

AgI and AgCl reduction potentials

The reduction potential for $\ce{AgI}$ is $-0.15\ \mathrm{V}$ and for $\ce{AgCl}$ it’s $0.22\ \mathrm{V}$. As $nFE =-\Delta{G} = T\Delta{S} - \Delta{H}$ this must imply that $\ce{AgI}$ is a stronger ...
3
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1answer
80 views

Which causes of quenching increase specifically in electrochemical experiments?

If quenching is seen as a result of running electrochemical experiments on a solution, what kind of processes may be responsible? I'm thinking about UV/Vis spectroscopy, if it makes any difference. ...
6
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2answers
1k views

Change in current in an electrolytic cell over time

Why does the current increase over time in an electrolytic cell with a $\ce{CuNO3}$ electrolyte. The current increased about $2~\mathrm{A}$, and the temperature increased during the experiment to ...
4
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1answer
47 views

The property F in an equation for chemical potential

While studying the lamba sensor that works on yttria-strabilised-zirconium (YSZ) I came across the following equation: $$p_{O_2}^{gas}=p_{O_2}^{ref} \cdot \exp\left(\frac{4FV_{ref}}{RT}\right)$$ ...
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0answers
320 views

Why does an increase in temperature decrease the electrode potential? [duplicate]

According to the Nernst equation, the electrode potential $E$ is $$E = E^\circ - \frac{RT}{nF}\ln\frac{[\ce{M}]}{[\ce{M^{$n$+}}]}$$ Question is, why? Assuming a simple galvanic cell, we know that in ...
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0answers
1k views

What is the Difference between difference between Standard Electrode Potentials and Standard Reduction Potentials?

As the question suggests I am wondering the difference between standard electrode potentials and standard reduction potentials. I know that they are both a measure of the Voltage from certain ...
3
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0answers
672 views

Calculation of optimal current density

I'm trying to figure out what my optimal current density would be in respect to the limiting current density. How do you calculate concentration polarization and limiting current density in an ...
14
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1answer
343 views

Does the Battery Bounce Test actually work?

I heard that a good way to test if a battery is dead or alive is to see if it bounces. Supposedly, dead batteries bounce higher than living ones. Can someone tell me if this is a legitimate claim, and ...
6
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1answer
980 views

Does water vapor in the air oxidize copper?

My friend is installing copper pipes in his house, which is going to be in a humid area, and he says that copper will only be oxidized by the air and the excess water vapor in the humid air won't ...
3
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1answer
9k views

Principle of potentiometric titration

In potentiometric titration between ascorbic acid and iodine, when we plot the graph of EMF with volume of iodine consumed, we get a sudden decrease in EMF at equivalance point--why? It is also ...
5
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2answers
490 views

Formation of species in electrolysis

I understand the principles of electrolysis of salts in aqueous solutions, but there are two points on which i am unsure. At the positive electrode, how can you work out which ions will ...
0
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1answer
64 views

What is the origin of the transferred oxygendianion in redox reactions?

How come the oxygens transferred in redox reactions are always the $\ce{O^{2-}}$anion? For example, I have this set of rules, and the rules are implicitly referring to the $\ce{O^{2-}}$ anion, a ...
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0answers
455 views

How to determine limiting conductivity of specific ions?

Given a table with equivalent conductivity of certain electrolytes, how can I determine the conductivity of separate ions? I know that you can find the difference between for example $\ce{K+}$ and $\...
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1answer
452 views

Can we create a galvanic cell with only half a cell connected to the ground? [closed]

I have a question about electrical potential in galvanic cells ,suppose that we have only half a cell wich means that we have only one Ox/Red couple (one metal and the other as ionic solution ...)...
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0answers
189 views

What is the purpose of the solution in a galvanic cell?

In other words: What is the purpose of the solution that the electrodes are immersed in, in a galvanic cell, and is it possible to generate a current without any solution?
12
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2answers
16k views

Conducting current in electrolytes

I keep trying to figure out how current is conducted through an electrolyte but all I can find are BS half answers. They say the ions conduct, but the specifics are poorly explained or absent. I ...