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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52 views

What is the electrolytic bath used in gold-plating of copper articles?

The answer is $AuCl_3 + NaCN$ Now I understand that for electroplating, we need gold to be deposited on the copper article, and the electrolyte must enable that deposition. But I don’t know what is ...
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15 views

Oxidative phosphorylation analogue

Does the salt bridge in galvanic cells resemble the ATP pump in the inner mitochondrial membrane? And if yes than did someone use this pH difference in harvesting this energy?
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Competing half reactions in electrolysis of aqueous solution of sodium hydroxide

If you run a direct current using pure nickel electrodes through a solution of NaOH in distilled water, you will separate the water into hydrogen and oxygen. Are there any other reactions that could ...
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21 views

Greater ligand stabilization of the lower oxidation state increasing redox potential

According to Atkins, P.W., De Paula, J. and Keeler, J., 2006, Atkins' Physical Chemistry, $$ \begin{align} \ce{[Fe(CN)6]^3- + e- &<=> [Fe(CN)6]^4-} &\quad E^\circ &= \pu{+0.36 V} \...
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1answer
598 views

Kohlrausch Law and conductivity

Im writing up a lab report at the minute and part of it concerns ions in solution and how they affect conductivity. I've been doing lots of reading and I think ive got the grasp of most of it, but its ...
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40 views

What is the correct definition for the activation Gibbs energy?

i found several definitions of the activation energy in electrochemistry, but i dont know why they are different. For example in Atkins "Physical Chemistry" the activation gibbs energy is defined as: ...
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1k views

Explain why can't zinc be plated out from a Zn(II) solution using standard reduction potentials

I am currently learning about electrochemistry using Zumdahl's Chemistry [1, pp. 709–710]. One of the critical thinking questions is Why can $\ce{Zn}$ not be plated out from an aqueous solution of $\...
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27 views

Current reversal in galvanic cell according to Nernst equation

In a galvanic cell with zinc, zinc sulphate solution and copper, copper sulphate solution, if at equilibrium concentration of zinc sulphate solution increased/copper sulphate solution decreased, will ...
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68 views

How to calculate the value of heat absorption/ heat release during water electrolysis?

The overall reactions with the enthalpies of water electrolysis at room temperature can be represented by the equation below: $$\ce{2H2O + \pu{237.2 kJ mol-1} + \pu{48.6 kJ mol-1} → 2 H2 + O2}$$ ...
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94 views

How does a pH glass electrode work?

Every source I read mentions the potential difference building up at the glass membrane (according to the Nernst equation). But how is this difference actually measured? Sticking an electrode into a ...
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138 views

What is the ideal temperature and pressure to crack water?

Using sun mirrors and solar cells for electricity. What temperature, pressure and voltage ideal for cracking water. Source: NPR Source Would it take more or less electricity to crack water under ...
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17 views

Why do electrocatalysts based on polyoxometalates and carbon materials have a weaker activity/performance in acidic media?

I am testing now some doped N and S doped carbon nanomaterials alone and immobilized in POM for the purpose of developing a nanocomposite that can serve as an electrocatalyst for energy-related ...
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45 views

Existence of single ion activities

I have used Davies equation to find what I believed was single ion activities and multiplied them on concentrations to define the thermodynamic dissociation constants for any kind of buffer to find ...
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33 views

How to Separate Copper Nanowires in an Alumina Membrane

So, in my Chemistry Lab we had an experiment to use Whatman alumina membranes and GaIn eutectic to create Nickel nanowires through electrodeposition. So essentially Nickel wire electrode and alumina ...
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118 views

The effect of the voltage at the Downs cell

I referred the Wikipedia and Advance Chemistry by Philip Matthews, for having a much comprehension on the down cell, but there was a opposition while reading the both references. Wikipedia states ...
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50 views

Why are signals broadened in polarography?

In the attached polarogram from Heyvrovsky's 1959 Nobel lecture, transitions from one plateau to the next are smoothened out rather than sharp and abrupt. Why is that? I understand that currents were ...
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8k views

Electrolysis of concentrated sulphuric acid

In my textbook it is given that for electrolysis of dilute sulfuric acid at anode following reactions can occur: At moderate concentrations $\ce{2H2O -> O2 + H+ +4 e-}$ And for high ...
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363 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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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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28 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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106 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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60 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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400 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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260 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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418 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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156 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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237 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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93 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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122 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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790 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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652 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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495 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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101 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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90 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 equation ...
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4k 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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89 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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45 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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121 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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740 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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344 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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104 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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625 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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758 views

Cell voltage required for refining copper

If you put Zinc or Iron solids into aqueous copper (II) sulphate solutions, copper solids form spontaneously due to the fact, that Zinc/Iron oxides into ions more willingly than Copper does. And if ...
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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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988 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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61 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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846 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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