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).

314 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
2
votes
0answers
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 ...
2
votes
0answers
857 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 ...
2
votes
0answers
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 ...
2
votes
0answers
121 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?
2
votes
0answers
215 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 ...
2
votes
0answers
153 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 ...
1
vote
0answers
34 views

Question about reversible chemistries in anode and cathodes

I've been reading a lot about cathode and anode chemistries recently involving Li-ion cells and solid state chemistries. What makes a decent anode seems to make sense as it is a lower potential area ...
1
vote
0answers
24 views

Driving force of Galvanic cell

Work can be extracted from galvanic cell which has a negative Gibb's free energy. I was wondering what is the driving force of it: I would naturally think its the Gibb's free energy, but the gaps ...
1
vote
0answers
48 views

How to derive the Henderson equation for liquid junction potentials given in Bard and Falkner?

The general equation for liquid junction potential is given by $$E = {-RT\over F}\sum_i\int_a^b{t_i\over z_i}d ln(a_i)$$ Where a and b are the two phases, $t_i$ is the transport number of the ions and ...
1
vote
0answers
34 views

In electrophoresis, are positive and negative molecules obviously separated?

I have just studied electrophoresis in biochemistry. The charged particles move to the oppsite charged electrodes whose speed is depended on their particle size. If that so, are negative and positive ...
1
vote
0answers
38 views

In Na extraction, is Ca2+ of CaCl2 reduced in addition to Na+ of NaCl in electrolysis

In Na extraction from $\ce{NaCl}$, $\ce{CaCl2}$ is added in electrolysis to lower the melting point of the mixture to about $\pu{750 ^\circ C}$. But doesn't $\ce{Ca^2+}$ cation compete with the $\ce{...
1
vote
0answers
27 views

What is the relationship between current flow and low AC voltages within electrolyte solutions

I have recently been trying to find references or textbooks which may explain the principles of electrical current conductance within an electrolyte solution when low AC voltages are induced. Does ...
1
vote
1answer
79 views

Copper brightness change

In an electrolysis situation I have identified a slight brightness change on a copper electrode. What might have happened? I'm dealing with different experiments and this reaction occurs in some of ...
1
vote
0answers
144 views

Are the reactions in a simple cell overall exothermic? Why?

For context, I'm in high school. I'm trying to mentally connect electrolysis with the concept of energy changes and kinda having trouble. I understand the bottom line is that a simple cell converts ...
1
vote
0answers
46 views

Equilibrium cell potential question

In an attempt to wrap my head around the basics of electrochemistry I'm working my way through Wesley R. Browne's 'Electrochemistry' primer. With regards to the equilibrium potential of an ...
1
vote
0answers
48 views

Calculating Ka using Nernst Equation

I've heard multiple times that the Nernst Equation could be used to calculate K$_a$. How would one calculate the acidity constant, K$_a$, of a specific acid, using the Nernst Equation? The equilibrium ...
1
vote
0answers
34 views

Specific conductance of KCl

Question: A conductivity cell containing distilled water has a resistance of $\pu{454 k \Omega},$ while the same cell containing $\ce{KCl}$ solution prepared in the same sample of water shows ...
1
vote
0answers
17 views

Which is the best kind of filter papers to use to extract silicon nanoparticles after acid wash, hydeophobic or hydrophilic?

I'm looking for filter papers to extract silicon nanoparticles after acid etching. I found that much of my material is get wasted with my Whatman Grade 4 filter paper. I am thinking to use membrane ...
1
vote
0answers
37 views

What is the activation energy of a Daniell cell?

I'm having trouble finding a posted literature value for the activation energy for the Daniell cell redox reaction: $$\ce{Cu^2+ + Zn -> Cu + Zn^2+}$$ Where might I be able to find this ...
1
vote
0answers
272 views

Electrical conductivity and the limits of Kohlrausch's law

I am currently writing a lab report on electrical conductance and I realized that my partner prepared $\pu{0.1 M}$ solution instead of $\pu{0.01 M}$. Now, I am supposed to find the molar conductivity ...
1
vote
0answers
63 views

Why does changing the salt of the salt bridge effect the voltage produced in a galvanic cell?

My experiments results showed that the voltage decreases down $\pu{Group 1}$: $\ce{Cl-}$ salts in the salt bridge. All other variables were kept constant. $\ce{Zn}$ and $\ce{Cu}$ rods were used. ...
1
vote
0answers
90 views

What is the yellow compound formed in electrolysis of brine?

Last week, I tried to conduct electrolysis of brine in my house using copper electrodes and 6V battery. After sometime, the entire solution turned orange/yellow. The yellow substance formed a kind of ...
1
vote
0answers
35 views

Are there any chemical pathways or catalysts that could produce electricity from fossil fuels without combustion?

While fossil fuels are dense in energy, I have known only one way to retrieve energy from them, namely, to burn them. I wish we could have a way to get energy from them without combustion. Is there ...
1
vote
0answers
50 views

Help understanding Electrochemistry diagram

I was reading some literature when i came across the following figure and was wondering if someone could help explain it to me. I see on the vertical axis it is potential vs Li/Li+ and see that Oxides ...
1
vote
0answers
158 views

Electric fields in a galvanic cell

I have read hat there is two types of electric fields exist in galvanic cell.I understand E because of charges accumulated on electrodes but what about other E -field? What does cause this field and ...
1
vote
0answers
68 views

Why is E°(cell) not ∆E°cell?

$E^\circ_\mathrm{cell}$ is the EMF of the cell for a reaction with respect to standard hydrogen electrode (SHE). So why don't we represent $E^\circ_\mathrm{cell}$ or $E_\mathrm{cell}$ by $\Delta$ ...
1
vote
0answers
41 views

Why not create a latent heat battery?

Since latent heat is not sensible, it seems like it would be useful in creating an efficient battery. Sensible heat interferes with electron flow in standard lead-acid and other batteries. The latent ...
1
vote
0answers
31 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: $$\ce{Sn^4+(aq) + Cu(s) -> Sn^2+(aq) + Cu^2+(aq)}$$ $$E^\circ_{cell} = \pu{-0.21 V}$$...
1
vote
0answers
49 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 ...
1
vote
0answers
21 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 ...
1
vote
0answers
43 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 ...
1
vote
0answers
230 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 ...
1
vote
0answers
36 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 ...
1
vote
0answers
227 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 ...
1
vote
0answers
34 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 ...
1
vote
0answers
428 views

Does increasing the concentration of the anode electrolyte in a galvanic cell increase or decrease the voltage produced

Im in kind of a pickle here. I am using nernst equations to calculate the theoretical voltage produced for different concentrations of $\ce{Al(NO3)3}$. Reaction: $$\ce{2Al(s) + 3Pb^{2+}(aq)⟶2Al^{3+}(...
1
vote
0answers
53 views

What happens electrochemically when bird droppings corrode cars?

I think the metal of the car first goes through an acid corrosion, followed by an electrochemical corrosion. First, the uric acid in bird poop corrodes with iron: 2Fe+C5H4N4O3 -> C5N4O3Fe2+2H2. Then, ...
1
vote
0answers
327 views

How to calculate the cell potential after the reaction has operated long enough for the Fe2+ to have changed by some concentration?

Consider the cell described below at $\pu{261 K}$: $$\ce{Fe | Fe^2+ (\pu{0.925 M}) || Cd^2+ (\pu{0.981 M}) | Cd}$$ Given $E^\circ_\ce{Cd^2+ -> Cd} = \pu{-0.403 V}$, $E^\circ_\ce{Fe^2+ -> Fe} = \...
1
vote
0answers
45 views

why do I get chlorine gas production during electroetching?

I was electroetching stainless steel plates with table salt as electrolyte and the power supply was providing 5V, 6A when I placed the anode and cathode about .25 inches apart. I started smelling a ...
1
vote
0answers
33 views

Changing the CO2 concentration (adding or subtracting) inside a sealed vessel?

I am looking for a method of modifying the CO2 concentration inside a sealed container that is both precise and repeatable (C02 needs adjustment every time the container is sealed, also need to be ...
1
vote
0answers
28 views

Does the Nernst equation suggest voltaic cell voltage remains constant over time?

Say the following reactions are occurring in my voltaic cell: $$\ce{Mg->Mg^{2+} + 2e- +2.36V}$$ $$\ce{Cu^{2+} +2e-->Cu -0.34V}$$ Then, the Nernst equation would become: $$E_{cell}=2....
1
vote
0answers
189 views

What is the electrode potential at the equivalence point if concentrations of titrant and titrand are going to be zero?

Let's assume that the titrand is $\ce{Fe^2+}$ and the titrant is $\ce{Cr2O7^2-}$. Then $$E = E^\circ_\ce{Fe^{2+}/Fe^{3+}} - \frac{RT}{nF}\ln\frac{\ce{[Fe^{2+}]}}{\ce{[Fe^{3+}]}}$$ $$E = E^\circ_\ce{...
1
vote
1answer
355 views

what should be the onset potential using cyclic voltammetry?

I am working for PEM fuel cell cathode material. I am confused regarding the onset potential determination for my catalyst (CV attached, fig 1 is complete CV while fig 2 is its zoom image for clear ...
1
vote
0answers
21 views

Detection limit of selective ion electrodes

I've been studying about the selective ion electrodes and I came across a question which I seem to not be able to answer. It has to do with why the detection limit for iodide ions is lower than the ...
1
vote
0answers
33 views

Where does hydrogen evolution occur when aluminium amalgam is placed in water - aluminium or mercury?

Let's say a drop mercury is placed on clean aluminium sheet; mercury amalgam is formed. The solubility of aluminium in mercury and vise versa at room temperature is fairly low. If the entire sheet is ...
1
vote
0answers
16 views

Where to find information about galvanic deposition of various metals?

I am looking at the process to deposit Cu and Ag onto metallic surfaces using galvanic techniques. Unfortunately this works not as expected. For example I use 2 rods of Cu in a bath of CuSO4 with ...
1
vote
0answers
102 views

How does cyclic voltammetry in a electrolytic cell measure the precise oxidation potential?

From what I understand, the potential necessary to induce a current to flow in an electrolytic cell depends on both reduction potentials of the anode and cathode reactions, where E(cell) is comprised ...
1
vote
0answers
308 views

What effect does an increase in concentration of copper sulphate solution have on the rate at which copper is deposited at the cathode?

I have been studying electrolysis in school and was wondering whether a higher amount of copper sulfate solution would produce a greater mass of copper in an electrolytic cell with two copper ...
1
vote
0answers
71 views

What MnO2 and graphite do I need for making a dry cell battery?

I'm playing around with making my own dry-cell battery and I want to make sure I understand the pieces before diving into it. My plan is to make it like a layer cake: zinc sheet, paste of ...
1
vote
0answers
3k views

How does the cathode of an electrolytic cell drive the anode reaction?

Consider this electrolytic cell: In this cell, electrons from the anode of the battery travel to the cathode of the electrolytic cell, where hydrogen ions are reduced into hydrogen gas. This drives ...

1 2
3
4 5
7