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
2k 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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795 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 ...
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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- -> ...
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1answer
723 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
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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
196 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 ...
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1answer
325 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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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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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
305 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 $\ce{CO2}$ ...
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1answer
180 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 ...
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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 &&...
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1answer
76 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 ...
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1answer
995 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 ...
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1answer
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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 (...
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1answer
285 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 ...
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1answer
83 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. ...
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2answers
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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 ...
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1answer
50 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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372 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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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 ...
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696 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 ...
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1answer
385 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 ...
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1answer
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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 ...
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1answer
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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 ...
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2answers
519 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 ...
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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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464 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
461 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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191 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?
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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 ...
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How do I calculate the viscosity of a mixture of toluene and isopropanol?

I am trying to understand why my nanoparticles will only electrophoretically deposit in a non-polar solvent and a non-polar/polar solvent mix but not in the polar solvent. I am hoping to use zeta ...
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2answers
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Why can't a primary cell be recharged?

The explanation I have found is that primary cells have irreversible reactions, so passing current in the opposite direction cannot recharge the cell. But as far as I understood it, no reaction is ...
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2answers
5k views

Is there always a need for a salt bridge to let a galvanic cell work continuously?

I read in a book that "Sometimes, both the electrodes dip in the same electrolyte solution & in such cases we do not require a salt bridge". How is this possible?
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1answer
243 views

How does an electrolyte react to voltages below its electrolysis potential?

An electrolyte can be electrolysed by a voltage higher than the reverse reaction’s cell potential, while conducting a current in the process. But what happens at the electrodes when the applied ...
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1answer
53 views

Electrodeposition of Ni

How can one electrodeposit Nickel on a substrate using a liquid crystal template? substrate is Indium Tin Oxide coated plate and the template is cetyl trimethylammonium bromide(CTAB)+WATER+ETHANOL
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1answer
9k views

Standard electrode potential of a galvanic half cell is zero at equilibrium at standard conditions?

At standard conditions(at 1atm pressure and unit activity(1molal or 1molar concentration)of all dissolved compounds),the electrode potential is equal to the standard electrode potential by the Nernst ...
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1answer
542 views

Plotting ΔG vs Temp for Electrochemical Reaction

I’m doing an electrochemistry lab that requires me to construct various galvanic cells in an attempt to solve for $\Delta H$, $\Delta G$, and $\Delta S$ values of an unknown. During one part of the ...
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Finding one of the two unknown potentials with a given voltage of a net reaction

A half-cell consisting of palladium rod dipping into a $1\ M$ $\ce{Pd(NO_3)_2}$ solution is connected with a standard hydrogen half-cell. The cell voltage is $0.99\ volt$ and the platinum electrode in ...
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1answer
191 views

Electrochemistry - Redox & Electroplating

I've stumbled across a problem that I need help on, it is mostly Electrochemistry and I will show my work. Line Notation Error: $$\ce{Fe~|~Fe^{+2}~||~Cl^{-},Cl2~|~Pt}$$ After that, I ...
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Basis set in the computational software “Gaussian-03” for studying adsorption of a hydrogen atom on a carbon paste electrode dropcasted with Pt-CNT

What is the basis set in the computational software "Gaussian-03" that can be used to study the interaction of $\ce{H}$-atom with $\ce{Pt-CNT}$ dropcasted electrode? How can we study the energy ...
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1answer
71 views

An electric potential is generated when a liquid moves with respect to a solid (streaming potential). Is the reverse true?

Streaming potential is an electrochemical phenomenon that a that relates electric currents with the relative movement of solid and liquid phases in contact with each other. So when a liquid moves ...
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1answer
2k views

Delta G for Standard Hydrogen Electrode reaction

I’m dealing with electrochemistry problems. For the following reaction $$\ce{2H+ +2e- <=>H2}\quad E^\circ=0\ \mathrm{V}$$ Does it make sense to say $$\Delta G^\circ=-nFE^\circ=0$$ Which would ...
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1answer
2k views

Does the relationship equation between standard cell potential and equilibrium constant violate potential's intensive properties?

The equation: $$E^{。}_{cell}= \frac{RT}{nF}\ln K_{eq}$$ We all know cell potential is intensive, not affected by the amount, Because: $volt=\frac{joule}{coulomb}$. Both joule and coulomb will be ...
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2answers
94 views

Transistors: How does the gate work?

Two questions: First, how does the gate provide a positive charge by running a current through it? I really just don't see how this positive charge could be achieved, unless you had some sort of ...
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1answer
1k views

Accelerated Oxidation Of Iron When Coating Breaks

I was presented with the following information: If iron is painted, then oxygen and water are prevented from contacting the metal, and corrosion is avoided. Sometimes the iron is coated with a thin ...
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2answers
633 views

How is a car battery recharged?

When recharging a lead-acid battery, how are the terminals of the battery connected to the voltage source. I mean, do we connect the positive terminal of the battery to the negative terminal of the ...
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2answers
2k views

What's the source of electrical energy in galvanic cells?

Let's take a simple Daniell cell for example: Where does the energy required to drive electrons through the external circuit and power up devices (like a light bulb) come from? Does the oxidation of ...
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1answer
301 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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1answer
4k views

Electroplating a spoon (electrolytic cell) using a electrochemical voltaic cell

I drew a rough picture of the two cells, and marked each position with a distinct letter: The whole reason I am asking this question is that I am bit confused and unsure about some of the chemistry ...

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