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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6
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2answers
7k views

Why put zinc solution in a galvanic cell?

In a galvanic cell with Cu and Zn electrodes, I was taught that each electrode is immersed in a solution containing it's own positive ions. I understand why you need copper ions, so they can gain ...
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1answer
411 views

Does the electrochemical series reverse in electrolysis?

Are these two statements true? In a galvanic cell at standard lab conditions (SLC), the strongest reductant is $\ce{Li (s)}$ and the strongest oxidant is $\ce{F2 (g)}$. In an electrolytic cell at SLC,...
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1answer
1k views

How to use the Nernst Equation

So I understand the Nernst Equation, but I don't have some info. (Please bear with me, I'm in secondary.) I'm doing a Cu - Al cell. My E cell is negative (-1.33). Does this have an affect on the ...
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0answers
212 views

Inert in Cathode when Electrolysis

Why Platinum, Gold, Carbon are inert? In electrolysis, it's not react in anode because anode is doing oxidizing, but how about cathode? Are they still inert?
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3answers
23k views

What is Molar Conductivity of an electrolytic solution

Please explain the physical meaning it carries ? And how is it that it can increase with dilution ? And why is it called Molar ? And what is equivalent conductivity ?
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0answers
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Why is the electrode potential of copper positive when hydrogen is more electronegative than copper?

Both copper and zinc has an electronegativity that is smaller than hydrogen, but why does copper have a positive electrode potential while zinc has a negative one? And lead (which has a greater ...
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1answer
182 views

Ordering the activity of metals [closed]

So I'm stuck on this question because I'm having trouble breaking it down. So I know the answer already but like most stuck students I'm not sure how to get to it. The problem is that I am not sure ...
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1answer
1k views

Does Copper reacts with Sodium Sulfate solution?

Okay I am trying to make a capacitor in which current collector is copper foil and electrolyte is sodium sulfate. Would this work? Do these two react with each other or not?
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1answer
856 views

carbon electrodes have potential difference even with no electrical input?

What is happening in this photo? I set up a simple electrolytic cell today of copper (II) sulfate solution with carbon electrodes. It was connected to a powerpack (set at ~8.0V), and a variable ...
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1answer
1k views

Why is zinc sulfate used in daniell cell [duplicate]

Why is zinc sulfate needed in the construction of a daniell cell. It seems that because the zinc is getting oxidized and not reduced there is no need to have a solution of zinc sulfate as it will ...
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1answer
515 views

The conversion of energy during electroplating

I've made a test and i've faced a problem with a part of a question which says: "What is the conversion of energy occuring in electroplating? " I answered that it is conversion from electric energy to ...
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1answer
1k views

Green color substance forming during electrolysis

A green-colored substance formed during electrolysis, wherein the electrolyte was magnesium sulfate and minerals in tap water. I did not have any leads to stick into the water, so I just put a 9 ...
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1answer
2k views

Using AC voltage for electroplating

As I know, in electroplating method, the type of voltage used is DC voltage. My question is, does replacing DC current supply by AC one affect the functioning of the cell? And why?
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2answers
17k views

Why does decreasing the distance between the electrodes in an electrolytic cell increase the rate of electroplating?

I did an experiment on the effect of the distance between the electrodes on the rate of electroplating in an electrolytic cell (copper electrodes with copper sulfate electrolyte). As I expected, when ...
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3answers
2k views

Is electrochemically activated water a real technology?

In essence what I'm asking is if the applications of Electrochemically activated water (ECA water) as a bactericidal-disinfectant is real and profitable (especially this last part). The principle at ...
4
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1answer
288 views

Making a non-CN dissolved gold solution ideal for electroplating

I've had success electroplating $\ce{Ni}$ and $\ce{Cu}$, but interestingly never $\ce{Al}$. My focus here is on plating with $\ce{Au}$, specifically onto an $\ce{Ni}$ surface. In general from my own ...
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2answers
685 views

Lithium batteries a reality - why not sodium, pottasium batteries?

Lithium batteries seem to be mainstream now, offering high energy density, high output current capability. Stepping down the periodic table there are alkali metals with greater electronegativity than ...
3
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1answer
1k views

Overpotential for photocatalytic water-splitting with TiO2

What is the meaning of overpotential in the context of photocatalytic water-splitting? That is light drives charge separation inside TiO2 and the generated electrons and holes react with water to ...
3
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1answer
369 views

Why is the cathode reaction required in a fuel cell?

So, at the anode of a fuel cell hydrogen is split into a positively charged proton and an electron. Then, there is the membrane which can let only protons through to the cathode, whereas electrons ...
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1answer
118 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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0answers
482 views

How to measure resistance of a gel electrolyte using a multimeter [closed]

How can I measure the resistance of a gel electrolyte using a multimeter? I know the formula to measure the conductivity of a gel electrolyte is k = (1/R) * (d/a) where k is the conductivity (S/cm), ...
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0answers
914 views

Few basic questions about ionic bonding and batteries (lead)

I've got a few very very basic questions about ionic bonds and their role in batteries. My assumptions (correct me if I'm wrong): Ionic bonds occur between a metal and a non-metal (the non-metal ...
4
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1answer
138 views

How could a rechargeable battery recharge itself?

I'm an engineering student preparing for my graduation, in one step of my graduation project I used a rechargeable battery(1.2 volt), i was shocked when this battery is starting to recharge it self ...
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4answers
379 views

Varying potential diffrence between two graphite strips in NaCl solution

I have two identical graphite strips of dimensions 3.5 cm by 1 cm. Both are 3/4 submerged in aqueous $\ce{NaCl}$ solution (0.34 mol/dm$^3$, 2% wt) separated by a distance of 7 cm. I have attached ...
5
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1answer
135 views

Why can some redox half-reactions be combined and some cannot? [duplicate]

I mean by "combining" is to make a new half-reaction equation and not an overall equation for a reaction in whole. For instance, I was trying to arrive at the following half-reaction: $\ce{MnO2(s) + ...
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3answers
199 views

protecting contact between aluminium and copper wires

The quarters in which I live has both aluminum and copper household wiring. This results in corrosion of the contacts and can lead to sparking, overheating, and even fire. Is there any way to ...
5
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1answer
170 views

Does battery self discharge when connected?

I am an electric engineer, and I read about battery self discharge phenomenon. I was wondering whether a battery self discharge rate is the same when it is unconnected (i.e. in storage) and connected (...
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5answers
301 views

How could I create a machine that as rapidly as possible creates greenhouse gases from air?

For a very large-scale project, I am trying to create a greenhouse gas demonstration device, which rapidly produces greenhouse gases from atmospheric air using only electricity, or any chemical ...
6
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1answer
1k views

Why soak filter paper in K2SO4?

From a description of my experiment: Potassium iodide crystals are place in the middle of filter paper soaked with potassium sulphate and phenolphthalein. Two electrodes are placed on the filter on ...
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1answer
3k views

Determining number of electrons transferred

When determining the number of electrons transferred in a redox reaction is it the total in both half equations? For example: $$\ce{2I- + Zn^2+ -> I2 + Zn}$$ First we split it up into the two ...
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1answer
106 views

Electrode Potential Half Reactions

Does flipping a reaction as written change the sign of the value of E or is it a completely different value? For example if I have the value for the half reaction $\ce{Cl2 + 2e- -> 2Cl-}$ but ...
2
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0answers
120 views

Shift of the null half-reaction potential

If we change the null half-potential, would it change half-potentials of other half-cell reactions by the same amount, so that voltages of net reactions stay the same?
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2answers
159 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
1k views

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 ...
5
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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?...
3
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0answers
42 views

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
6k 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
962 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 ...
2
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1answer
276 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
282 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
61 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
134 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
866 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
7k 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
707 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
474 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
191 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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