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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349 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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236 views

Electrodes involving sparingly soluble salts (Electrodes of the second kind)

Consider the sparingly soluble salt, $\ce{AgI}$ ($K_\text{sp} = 8.52\times10^{-17}$) and a silver electrode (Standard Reduction Potential = $\pu{0.799V}$). $\pu{0.02L}$ of $\pu{0.001M}~\ce{KI}$ ...
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18 views

why do we modelize an electronic double layer with a classic capacitor?

in an electronic double layer, there is a voltage drop between the metal and the solution but in the litterature, scientists always modelize EDL with a classic capacitor. My question is why ? because ...
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27 views

Is flow battery cycle life really as high as the literature claims?

I've seen a few reviews/journal articles now which claim that flow battery cycle life reaches the 10,000 mark and beyond with good capacity retention. However all of the primary sources I've came ...
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95 views

What can explain the more weight gain of aluminum coated steel than non-coated steel after NaCl immersion?

I have a 2 week experiment. I put aluminum coated and non-coated steel of the same size and shape in separate beakers with NaCl solution. Both are sealed. But, I am surprised that Al coated steel ...
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55 views

What are the effects of Ag/AgCl electrode liquid interface contamination?

I have been using a $\ce{Ag/AgCl}$ electrode with a porous teflon tip to measure open circuit potential between two electrodes separated by a membrane. I am worried that reagents such as iron chloride ...
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340 views

What is the effect of the surface area of an electrode on the emf of a cell?

I've read that a platinum electrode has no effect in a hydrogen fuel cell - why is this? Also, what is the effect of the surface area of an electrode such as zinc in a zinc copper cell?
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28 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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233 views

Electrochemistry: Does ion flow from one half-cell to another?

My textbook says one of the functions of a salt bridge is that "it completes the circuit by allowing ions to move from one half-cell to another". However, according to my understanding, only the ions ...
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340 views

Copper (II) oxide during CuSO4 electrolysis

I was performing copper (II) sulfate electrolysis (graphite electrodes; 10V; 0,01A) today and I observed black precipitate falling from around cathode. I suppose it's copper(II) oxide. I couldn't find ...
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145 views

Physical Chemistry: Calculating ΔG, ΔH, ΔS on a given equation

This question was brought in class, but I have no clue if my answer is correct or not. I wonder if you guys can double check my answer. Between $\pu{0 ^\circ C}$ and $90 ^\circ C$, the potential ...
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200 views

Would an aqueous solution of Zn(2+) develop a positive charge if solid zinc was dipped into it?

Say you have a beaker containing $\pu{1M}$ solution of $\ce{ZnSO4}$. The solution will be electrically neutral because there will be an equal number of cations and anions. If you then put a zinc ...
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82 views

How to slow/prevent corrosion of a steel post

I have a steel post set in limestone, about 18-20 inches deep, with some concrete around it. I just noticed that I have about 6 inches of water inside the post. The limestone had a small seam in it ...
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2k views

equilibrium state of a galvanic cell

At what conditions does equilibrium attain in the galvanic cell. What exactly happens at the equilibrium state of a galvanic cell redox reaction. Consider the setup Zn|Zn2+||Cu2+|Cu, Where Anode: $...
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117 views

CV redox peaks and Gamry Potentiometer

I'm using Gamry Potentiometer for taking CV measurements for finding the appropriate voltage values for oxidation/reduction peaks and Echem Analyst for analyzing. CV measurements has performed on ...
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352 views

Understanding Chemical Potential (Li-ion)

Can anyone help me to understand what the "Chemical Potential" is? I can see that in batteries the electrical energy is stored as "chemical potential", according to this: Li-ion batteries, Na-ion ...
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1answer
726 views

How exactly does a battery work (specifically Pb/H2SO4/H2SO4/PbO2 lead acid battery)?

Specifically talking about the lead-acid battery, I understand (or think I understand) this much: The anode, in the presence of the electrolyte, $\ce{H2SO4}$ will be oxidised: $$\ce{Pb (s) + SO4^2- (...
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1answer
3k views

Why does NaCl act as a catalyst for the reaction of CuSO4 + H2O + Al?

I am analyzing a reaction between water sulfate copper and aluminum. A chunk of $\ce{Al}$, e.g., aluminum foil. I realize that a layer of $\ce{Al2O3}$ forms on the surface of the $\ce{Al}$, ...
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567 views

Problems with Daniell cell

In Zemansky and Dittman's book on thermodynamics, pages 41–43, the authors discuss the Daniell cell as a thermodynamic system. Their cell consists of two saturated $\ce{CuSO4}$ and $\ce{ZnSO4}$ ...
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598 views

Efficient oxidation of KCl to KClO3

I am trying to convert $\ce{KCl}$ to $\ce{KClO3}$ through an efficient process. I realize that I could electrolyze a solution of $\ce{KCl}$ to obtain some $\ce{KClO3}$ as a precipitate, however this ...
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413 views

Electrolysis of dilute and concentrated sodium chloride and the Nernst equation

Interested to know if there is a critical concentration at which $\ce{Cl-}$ will oxidise over $\ce{H2O}$ and if this can be determined using the Nernst equation. That is, obviously if $[\ce{Cl-}]>...
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82 views

Laws of electrolysis and quantisation of charge relation

The quantisation of charge was first suggested by the experimental laws of electrolysis discovered by Faraday I think about it a lot but could not find any relation, as the number of electrons ...
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87 views

Effect of passing hydrogen sulfide gas on electrode potential

Consider the cell reaction $$\ce{2Ag+ + Pb <=> 2Ag + Pb^2+}$$ If $\ce{H2S}$ gas is passed through the solution, what will be the effect on the EMF of the cell? My attempt: The Nernst ...
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3k views

What does electrolysis of Cu(NO3)2 produce?

I have read that $\ce{Cu}$ is deposited at the cathode when copper (II) nitrate is electrolyzed. However, when I looked at reduction potentials, the reduction of nitrate to $\ce{NO}$ and $\ce{H2O}$ $(...
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82 views

What are the chemical formulae for galvanic corrosion of iron (rusting)?

The conditions for corrosion, I am searching equations are as follows: The other metal is copper The temperature is $25~\mathrm{^\circ C}$ The electrolyte is $\ce{NaCl}$ pH 7 A limited amount of ...
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44 views

How do I analyze Mg<->C galvanic cell?

I've made a battery for middle school, and I want to figure out the chemistry, especially so I can say whether the little bubbles in there are $\ce{CO_2}$ or hydrogen. In salt water, I have a strip ...
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117 views

How does a cathode half reaction work with different metal electrode and electrolyte

If you had a galvanic cell with the cathode half cell using silver as its electrode and Copper Sulfate as its electrode, will the copper (s) coat the silver electrode?
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4k views

Calculating Solubility Product of AgCl from electrode potential

I have to use a measured electrode potential to find the solubility product of $\ce{AgCl}$. In our experiment, we first mixed one drop of $\pu{1.0 M}$ $\ce{AgNO3}$ with $\pu{10 mL}$ of $\pu{1.0 M}$ $\...
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596 views

What are some factors that influence the voltage of voltaic/galvanic cells and why?

Question: (2014 USNCO local exam Q#41): What types of changes would increase the voltage of a voltaic cell. I have learned a bit about voltaic cells, but I haven't been able to find information ...
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321 views

Understanding how potentiometry works

I want to make sure I understand this technique. I am reading information from this website. From what I can understand, you have it set up like a galvanic cell, but in the middle of the wire ...
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101 views

Determining Overall Equation and Oxidation Potential

Cell 1 is composed of a reference chloranil half-cell (standardised against SHE as $+0.680 \mathrm{V}$) connected to an $\ce{Ag/AgCl}$ half-cell containing saturated ($0.125\ \mathrm{mol\ L^{−1}}$) $\...
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513 views

Electrolysis of auric chloride solvent with different metals in anode and cathode

Question: Write down possible reaction in anode and cathode for electrolysis of $\ce{AuCl3}$ with solid $\ce{Au}$ electrode in anode and solid $\ce{Ag}$ electrode in cathode. As far, I could write ...
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1k views

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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821 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 ...
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59 views

Preparing CdSe electrodeposition bath

What is the best way of preparing an aqueous solution containing 5 mM $\ce{CdSO4}$, 1 mM $\ce{SeO2}$, 0.5 M $\ce{Na2SO4}$ and adjusting pH to 3 by adding 0.5 M $\ce{H2SO4}$? What is the ...
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783 views

Cyclic Voltammogram - How to determine Overpotential

http://youtu.be/1f92vGOridg Clicking on the link above will take you to a video with a diagram of a voltammogram. Through my own experiments I have managed to obtain a similar diagram. However, I am ...
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50 views

Electrochemistry lye quality

With the following setup: plastic container, water (impure), pencil (anode), tin foil (aluminum, cathode) and solar panels supplying electrical charge (roughly 36v at about 400-800ma), with the ...
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115 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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202 views

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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42 views

Would the detaching of dendrites from electrodes in a cell, result in the crystal dissolving back into the electrolyte?

Dendrites that form on the electrodes of cells shorten the cell's lifetime, and result in reduced capacity before the end of life. If the dendrites could be detached from the electrode, would they ...
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145 views

Will the current at the inversion potential of a CV trace asymptotically approach zero?

Reading up on the theory of cyclic voltammetry, I note that the current at the inversion potential (that is, the point at which the applied potential goes negative) in every reversible CV trace I have ...
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1answer
46 views

Why is the peak-to-peak separation of cyclic voltammetry is 57 mV?

I'm studying CV, and I wonder if I can calculate the peak-to-peak separation of CV for a reversible redox system. I found that the separation is 57 mV on my textbook, and my teacher taught me that is ...
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27 views

Calculating Equilibrium Constant from Cell Potential at Nonstandard Temperature

I'm currently working on a problem for a general chemistry class. This is the voltaic cell given in the problem: $$\ce{Sn^4+(aq) + Cu(s) -> Sn^2+(aq) + Cu^2+(aq)}$$ $$E^\circ_{cell} = \pu{-0.21 V}$$...
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20 views

Gibbs free energy calculation for redox reaction

I was wondering if it is correct to calculate the Gibbs free energy of reaction at $P = \pu{1 atm}$ and $T = \pu{1100 K}$ using the NIST-JANAF thermochemical tables. For example, for the reaction of ...
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15 views

Can a Titanium Grade 5 alloy produced by SLM have greater 'surface area' exposed?

I was doing an electrochemical test (LPR) and Titanium Grade 5 produced by AM respassivated oxide layer faster than the specimen produced with traditional manufacturing under identical experimental ...
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32 views

“Hairy” corrosion on anodized alu-part in water

I got a water tank with a mechanical assembly in. The assembly consist of parts of anodized aluminium mounted on stainless steel plates (AISI 304). This is submerged down in fresh water. The tank is ...
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42 views

What could be causing my cyclic voltammograms to have a sloped scan?

I am running a CV (cyclic voltammogram) in a two compartment bulk electrolysis cell with pH 7 phosphate buffer (0.5 ion concentration) and a napheon membrane separating the two compartments. I'm using ...
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35 views

Can carbon dioxide be used as oxidant for iron?

Determine whether it is possible for $\ce{CO2}$ to be an oxidant for $\ce{Fe}$. Justify your choice by comparing the corresponding half reactions. I found the following half-reactions, both on ...
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56 views

Can static electricity damage solar cells?

How does static electricity damage common solar cells making them less photo reactive? At watt voltage and/or amps would change the chemistry of the common solar cell? I want to think that as long ...
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28 views

Calculate chemical potentials to find electrode Fermi level

I'm running some simple simulations of the semiconductor-electrolyte interface and I'm having a hard time figuring out the equilibrium condition. Can someone please help me with my electrochemical ...