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
89 views

Why does it so long for a Lithium-ion battery to be charged from 98% to 100%? [closed]

Why does it so long for an Lithium-ion battery to be charged from 98% to 100%? It is not even comparable to the effort I exerce to pump my bike tires from 95 psi to (the minimally usable) 100 psi. ...
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32 views

Are the potentials of the electrolytes equal in Galvanic cell?

My book defines Electrode Potential for a Galvanic Cell as follows: A potential difference that develops between the electrode and the electrolyte is called Electrode Potential $$E= V_{electrode} - ...
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1answer
53 views

Can someone explain why the electrical conductivity of magnesium chloride decreases with increasing concentration?

I was under the impression that the electrical conductivity should increase initially, then begin to plateau, then fall past the saturation point for strong electrolytes. However, from this, I see ...
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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 ...
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Will a polymer exchange membrane work with chlorine and hydrogen instead of hydrogen and oxygen? [closed]

I want to feed chlorine and hydrogen from an electrolysis reaction (using water and sodium chloride) and in turn feed the product (hydrogen chloride) back into the electrolysis water to counteract the ...
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33 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 ...
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1answer
356 views

What is the optimal voltage for storing a 3.7 V lithium polymer battery?

According to this website, storing a lithium polymer (LiPo) battery/cell at around 40% capacity would be more beneficial for the lifespan of the LiPo cell comparing storing the battery at 100% ...
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2answers
41 views

doubt in Sign for electrode potential

I was thinking that what is the meaning of negative and positive values of reduction potential of an element. So i concluded that as in thermodynamics in physics we use $\Delta U=\Delta Q- \Delta W$ ...
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1answer
23 views

why is change in Enthalpy of a galvanic cell negative?

my teacher told me that change in enthalpy of a cell reaction is always negative but i can't get in what respect he said and why. Someone please give me a good thought?
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How is the following thermodynamic electrode potential equation written?

Why is delta G1nod and delta G2nod written i think that they should be same as delta Gnod is defined at STP so why are we taking T1 and T2
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Why is the anode in a Galvanic Cell negative? [duplicate]

Good day to all, I am currently studying Electrochemistry for the first time. I would like to know why the anode in a galvanic is negative ,without being told that the electron moves from Anode to ...
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Can I mix pressures and concentrations when finding equilibrium constant? [duplicate]

In order to find the equilibrium constant (or reaction quotient) I know I can find the value as the products over reactants raised to coefficient exponents. But, in all of the problems I have had to ...
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4answers
379 views

Explanation for a basic decomposition of water experiment

My son is trying to write a conclusion for a basic decomposition of water experiment using a 9 V battery (with a test tube placed over each terminal) placed inside a salt water solution. The results ...
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1answer
35 views

Carboxyllic acid Test

I'm currently in high school doing a project in chemistry. So I had to make a project where concepts from physical chemistry will be used alongside organic chemistry. After going through my book I ...
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1answer
32 views

Can the electrochemical stability of a aqueous KOH solution be increased by adding more KOH?

My goal is to increase the efficiency of a nickel-iron battery. One of the options to reach this goal is:suppressing the hydrogen production. Due to electrolysis, the electrolyt will start ...
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1answer
62 views

Sodium Sulfate or Sodium Carbonate for electrolysis in water

I am not a chemist but I have a question regarding electrolytes in electrolysis. I have done a lot of reading but cannot find the answer I'm looking for regarding Sodium Sulfate (or Sulfide) I intend ...
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What does a sigmoidal and non-sigmoidal shape of a oxygen reduction reaction (ORR) voltammogram mean?

While testing materials for their ORR performance, one can encounter linear sweep voltammograms that have a well defined diffusion plateau and a good sigmoidal shape. On the other hand, the opposite ...
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36 views

Questions About an Appropriate Textbook on Electrochemistry for Self-Study

Apologies if this is a somewhat frequent request (I promise I did scour various sources before posting, but none quite applied to me), but I was hoping for some insight from the community regarding an ...
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1answer
31 views

Redox and anode/cathode in lead acid battery

I have watch a video about lead acid battery and I am very confused about the way the half reactions are labelled. I have learned that oxydation is the loss of electron (so it's the half reaction with ...
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1answer
33 views

How does a body lose electrons? [closed]

If there is a Na and cl in solid form , There will be atoms inside of them.How do they lose electrons ?.We know solid body has a structure and covering.Just like you can touch is the covering of table ...
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2answers
54 views

How to make krypton gas glow

So hypothetically, if one was to buy krypton and wanted to make it glow, would a little tesla coil be enough to make it glow? If not, what would be enough? And would one be able to make it glow ...
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35 views

What is the relationship between the stability constant of a copper (II) electrolyte complex ion and the output voltage Ecell? [closed]

As a part of a school investigation I constructed a voltaic cell experiment where for each run I added a different ligands to the copper (II) sulfate half-cell electrolyte in a daniell cell to see if ...
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2answers
56 views

Calculating the cell potential of a half cell from two half cell equations [duplicate]

I understand the premise of the question and how to solve it but I don't quite understand why I'm a factor of 2 out: Construct a potential diagram (at $\mathrm{pH} = 0$) for the reduction of aqueous $...
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2answers
54 views

Easiest/Fastest way to obtain a good quantity of fine Iron powder? [closed]

I am wanting to make a reasonable quantity (10-100g) of iron powder that I can use to visualise magnetic fields (by putting the powder in a thin layer between two transparent materials). The finer the ...
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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 ...
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2answers
77 views

Copper anode dissolves in electrolysis of copper sulfate solution [closed]

I did an experiment with copper sulfate where you place two copper rods in an aqueous solution of copper sulfate. You apply an electric current and copper metal builds up on the cathode. I noticed ...
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1answer
86 views

Graphene in Lithium-ions batteries: why?

I have recently been reading about the amazing discovery of a super-material: Graphene. This one carbon-layer chemical is not only one of the most resistant materials ever known, but also one of the ...
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29 views

Methane Sensor electrochemical reaction

When using a methane sensor a voltage is applied and much like electrolysis if the voltage is above the decomposition potential a reaction happens. Flammable gasses like methane are easily oxidized ...
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1answer
68 views

Why is Sodium Transported Across the Cation Exchange Membrane in the Chlor Alkali Process?

In the Chlor Alkali Process, a sodium ion is transported across a cation exchange membrane to create NaOH in the Anode Chamber: The Half reactions are: 2Cl− → Cl2 + 2e− and 2H2O + 2e− → H2 + 2OH− and ...
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Is there a way to theoretically estimate the overpotential losses in a battery?

Me and my team are currently designing a battery and are looking to do some pre-experimental analysis of different battery chemistries based on their overpotential losses. I am aware of the Butler ...
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1answer
82 views

Cell potential for redox titration of iron(II) with cerium(IV) [closed]

Calculate $E_\mathrm{cell}$ for an electrochemical cell consisting of SCE and a platinum wire indicator electrode dipped in a titration vessel containing $\pu{25 ml}$ $(\pu{0.01 M})$ solution of $\ce{...
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2answers
64 views

How does current start to flow when galvanic cell is first connected?

Using the Daniell Cell as an example, where in the steady state we expect zinc to be oxidised and copper to be reduced spontaneously due to the overall reduction in Gibbs free energy, how does the ...
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1answer
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Why do batteries drain so quickly if they are forced to draw more current than they normally do?

When a battery is pushed to use twice the current it normally does, it lasts for less than half as long before dying... In fact, batteries often come with a 'C' rating that gives you an idea of how ...
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2answers
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How does work from other sources affect Gibbs free energy of the system?

In most physical chemistry textbooks, Gibbs free energy is given like this: $$\Delta_\mathrm rG = \Delta_\mathrm rG^\circ + RT\ln Q\tag{1}$$ and Gibbs free energy is part of this three-way ...
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2answers
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Does changing the electrolyte concentration in the electrolysis of water affect the speed that hydrogen gas is produced at the cathode?

I am currently completing a Year 12 Extended Practical Investigation. Due to the lock-down restrictions we are unable to complete our own practical experiment and have been given sample answers with ...
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2answers
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Can I use activated carbon electrod as a reference electrod in a pH meter instead of using murcury? [closed]

Activated carbon is less expensive than mercury . They are recyclable . Mercury is toxic. Nowadays activated carbon is being used in supercapacitors,Li-ion battery.
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1answer
84 views

Cell voltage with different n factors

I’m a bit confused regarding cell potentials. If I have two half reactions each involving a different number of electrons, there are two ways I can see to calculate the net emf of their cell: Simply ...
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2answers
99 views

Why does an electrochemical cell work?

My textbook says that an electrochemical cell works because of difference in reduction potential of two metals which cause one to lose electrons and other one to accept them. If a salt bridge is not ...
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2answers
67 views

Supporting electrolytes and increased conductivity?

Hi a question about supporting electrolytes (SE) I hope you can help with. I found some related questions here through searching but looking for a simple answer (if there is one!): If SE are ...
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2answers
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How does a battery create a potential differece (voltage)? [closed]

I'm 15 and recently started electronics and I just had a question about batteries. (I've been told by people on physics stack exchange to come here to have my question answered). From what I ...
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1answer
61 views

Standard electrode potential of copper disproportionation

I am having some difficulty with the below. It says the standard potential for $\ce{2Cu+ (aq) -> Cu (s) + Cu^2+ (aq)}$ is $\pu{0.36 V}$. The relevant half equations are: $\ce{Cu+ + e- -> Cu}$ (...
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37 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{...
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What surface treatment can turn nickel black?

Questions: The detailed surface treatment to turn nickel plated steel black. The reaction mechanism of the process. Methods: (preferred) Anodizing, oxidizing : The only black nickel oxide is $\ce{...
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1answer
60 views

if I have concentrated acetic acid (99%) what are the out put gases during electrolysis?

If I use concentrated acetic acid (glacial acetic acid($\ce{CH3COOH}$)) as an electrolyte. What ions are produced at the anode and cathode? Can I get ethanol with it ($\ce{C2H6O}$)? If not, what would ...
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1answer
44 views

What is the effect of putting salt on water during electrolysis [closed]

I want to decompose $\ce{H}$ ion and $\ce{O}$ ion by putting carbon electrode in the water, but it look so slow. What if I put sodium chloride? Would putting $\ce{NaCl}$ have effect on output gas($\ce{...
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1answer
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Would a voltaic cell still work if you replaced both the cathode and anode with a carbon/graphite electrode?

for example, in this cell: Zn(s)|Zn2+(aq)||Ag+(aq)|Ag(s) if you replace the silver cathode with a carbon electrode, i know it would still transfer electrons, but if you also replaced the Zinc ...
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36 views

Why I get acidic solution at brine anode?

I have decomposed $\ce{NaCl}$ solution (brine) with electrolysis and yield $\ce{NaOH}$ at cathode, at anode I got acidic while expected was $\ce{NaClO}$ (alkaline) if it is $\ce{HOCl + HCl}$. Where ...
2
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1answer
107 views

Electrolysis with baking soda solution, a penny as the cathode and graphite for the anode

I set up an electrolysis experiment to show my kids and wanted to explain to them what is happening. My setup has a penny as the anode and graphite for the cathode. The solution is water with baking ...
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3answers
106 views

White snow-like powder below sodium hydroxide solution [closed]

I have created sodium hydroxide solution with half cell brine electrolysis but, finally I got white snow-like insoluble powder sank below sodium hydroxide. What should I do keep or remove it?
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1answer
43 views

Conductivity of molten or aqueous salts [closed]

If there is a 1M aqueous solution of 1 liter NaCl (aq), and the molar conductivities of the solution and the chloride ions were found to be $x$ and $y$ respectively, is it accurate to say that the ...

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