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
77 views

Why should I not use different battery types together?

Everyone knows about this but I'm curious about why one should never mix batteries of different types. By type I mean the same shape of the cell like AAA but with different chemical reactions and ...
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1answer
96 views

Is it possible to electroplate from a gallium anode?

I have been looking at some papers on electro-deposition of iron gallium alloys and these all use solutions made up of Fe and Ga sulphates. I am just curious as to why perhaps an anode made of one of ...
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61 views

Can I make an ionic liquid from glycerin and zinc sulfate?

Can I make an ionic liquid (dissolved salt without water) by combining zinc sulfate and glycerin? I've been using 1 M $\ce{ZnSO4}$ as my electrolyte in supercapacitor study. Works very well up to ...
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1answer
303 views

What happens if you put a piece of copper into a solution containing Al3+ ions?

This is a question in my studies, and I am a little bit confused! I would think it happens nothing because copper is below aluminium in the reactivity series, right?
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1answer
279 views

How to calculate the electromotive force of a silver chloride/ silver bromide cell?

For the galvanic cell: $\ce{Ag|AgCl(s)|KCl(0.2M)||KBr(0.001M)|AgBr(s)|Ag}$, calculate the electromotive force (EMF) generated. $K_\mathrm{sp}(\ce{AgCl}) = 2.8\times10^{-10}$; $K_\mathrm{sp}(\ce{...
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1answer
306 views

Why does increasing the concentration of oxidizing agent decrease the E° in a galvanic cell?

In a galvanic cell, when we add ions of the oxidation agent (in this example, Zn2+) to the anode solution, it decreases the cell potential. However, if the Zn2+ ions aren't involved in the redox ...
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1answer
245 views

Replacing Salt Bridge with Platinum Sheet

What would happen, if in a galvanic cell, the salt bridge is replaced by an inert platinum sheet? Would charges accumulate on the sheet? Would the cell still work, and produce less emf than earlier, ...
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1answer
9k views

Which half cell equation do you switch when calculating E° cell?

Given the following standard potentials calculate the overall $E^\circ_\mathrm{cell}$: $$ \begin{align} \ce{Pb(SO4)(s) + 2 e- &→ Pb(s) +SO4^2-(aq)} &\quad E^\circ &= \pu{-0.356 V} \\ ...
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64 views

Regarding Standard Electrode Potentials

If the standard hydrogen electrode (SHE) is set arbitrarily to have a potential that is equal to 0 V, and has an absolute real potential. Then, in electrochemistry, how are the electrode potentials of ...
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63 views

What is the voltage dependence of the thickness of oxide coating through anodising?

In titanium anodising, solid titanium reacts with the oxygen formed at it's surface (to form titanium(IV) oxide or $\ce{TiO2}$) through the electrolysis of water. Experimentation and research has ...
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2answers
1k views

Salt Bridges/Porous Disks

I am slightly confused about the concept of a salt bridge/porous disk. I understand that these are necessary in a galvanic cell since there is a charge buildup and the salt bridge and porous disks ...
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24 views

Polarity of Cell Electrodes [duplicate]

I understand that the anode in a galvanic/voltaic cell is considered to be 'negative' while the cathode is 'positive'. However, in an electrolytic cell, the cathode is 'positive' while the anode is '...
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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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1answer
191 views

Pourbaix diagram and the order of the species

Figure 1. Pourbaix diagram of iron (Source) The line between $\ce{Fe}$ and $\ce{Fe^2+}$ is there because the potential $\ce{Fe/Fe^2+}$ is $\pu{-0.44 V}$. The same applies for $\ce{Fe^2+/Fe^3+}$ with $...
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100 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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3answers
98 views

What defines a discharged battery?

In the case of an AA Alkaline battery, what actually happens inside the battery once it is fully discharged? What components of the battery change as we use it?
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1answer
245 views

Electrolysis of water: Which equations to use? (IB Chem)

There is a list of standard electrode potentials at 298 K from the p. 23 of IB Data Booklet 2016. Which of the following equations (forward/backward reactions), from the two possible ones involving ...
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52 views

Where does copper form?

I thought zn and cu both lose 2e- to pt but someone is telling me it's wrong]
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1answer
167 views

Determining the reduction potential of a half cell reaction at a given pH

$E^\circ_\ce{Cu^2+|Cu} = \pu{0.34 V}$. What will be reduction potential at $\mathrm{pH} = 14$ for the same couple? Given that $K_\mathrm{sp}$ of $\ce{Cu(OH)2}$ is $10^{-19}$. My Attempt I think ...
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1answer
224 views

Can gas be made to block radiation better?

Can any gas block radiation? I ask this because I would like to know if the properties of any gas element would chemically react differently with radiation from adding an electrical current. This ...
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2answers
104 views

Why is reduction potential of water ( 2H₂O + 2e⁻ → H₂ + 2OH⁻ ) is -0.83 insted of 0, as in the case of (2H⁺ → H₂)?

I came across this value of reduction potential of water while solving a question. Also, I noticed that, for example $$\ce{Ag+ → Ag}$$ has a fixed standard potential, and the same is used when we do ...
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7answers
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Which is anode and which is cathode?

A maybe (hopefully) simple question about the denotations of "anode" and "cathode". The below image is a schematic of a polymer solar cell (Source (WBM)). (The figure text is quoted as well for the ...
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1answer
255 views

Confusion about the relation between gibbs free energy and electromotive force

$$\Delta G = -nFE$$ My textbook says that we can measure that this $\Delta G$ is measured when the work is done reversibly. But my confusion is how will we work reversibly when we have an ...
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1answer
148 views

Unknown salt formed from electrolysis of urine

I am not sure what I was expecting to happen with this but I created a circuit to electrolyze various household liquids. My electrodes are copper — or at least claim to be, I think they might just be ...
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2answers
122 views

Oxidation of metals/halogens by oxygen gas in acidic aqueous solution

I had some confusion about the correct answer to the following question: Which substance can be oxidized by $\ce{O2(g)}$ in acidic aqueous solution? Two of the answer choices were metal cations (...
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2answers
270 views

Still taught to reverse oxidation half cells in electrochemistry?

In a question, Oxidation of metals/halogens by oxygen gas in acidic aqueous solution, there was a point made that reduction half-cells should not be reversed. I was taught ($\approx 1970$) in the ...
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0answers
135 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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1answer
60 views

Metal that does not deposit silver (Ag)

Hi Chemistry enthusiasts! I am working on my scholarship exam practice but I am considered myself as a newbie so I would like to hear your opinion :) From (1)-(4) below choose the metal that does ...
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0answers
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 ...
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2answers
414 views

Using a calcium metal anode in aqueous solution?

In school, I am doing an electrochemistry lab in which I need to create a galvanic cell battery with the highest voltage possible using two beakers, a salt bridge, and electrodes. To maximize the ...
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3answers
316 views

What is the flow of electrons, cations, and anions in a voltaic cell (please see image attached)?

This is an IB question. The mark scheme says that the correct answer is A and only A. But I believe B is also correct. The following is my thought process. Since A is more reactive, it undergoes ...
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2answers
70 views

For Hess' law type questions, when do you take the inverse of the constant and when do you switch the sign?

For example, when you're given the enthalpy $\Delta H$ of a reaction and you want to switch that reaction around in order to add it to something else, you switch the sign. Furthermore, when adding ...
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3answers
15k views

What is the difference between molar conductance and molar conductivity?

I'm learning (or at least trying to learn) about electrochemistry, but a major obstacle to that, is that different books I refer use different terms for the same symbols. So in a last ditch attempt to ...
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1answer
57 views

Would electrolysis work with a conductive (but waterproof) divider between anode and cathode?

Note I am not trying to "double fuel efficiency" in a car or something scamey like that. My purpose is to fill balloons with hydrogen and possibly power an HHO torch (also make it safer because pure ...
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1answer
774 views

[Co(H2O)6]3+ vs [Co(NH3)6]3+ oxidising water

Cobalt(III) complexes cannot be prepared by addition of the ligand to a solution of the metal cation because the aqua cation $\ce{[Co(H2O)6]^3+}$ has no stable existence in solution. It is strongly ...
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1answer
53 views

What do electrons usually do when lead acid battery is idle?

Lead acid batteries operation are governed by Redox reactions for charging and discharging. But, what do electrons usually do when lead acid battery is idle? And why? Assumptions: Say more ...
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4answers
114 views

Reduction Potentials [closed]

Standard electrode potential values can be used to judge the reducing ability of a metal. When I was introduced to this topic a simple picture was painted: you put a metal into a solution of its ions. ...
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3answers
107 views

Confusion on electrode potentials

Standard electrode potential values can be used to judge the reducing ability of a metal. When I was introduced to this topic a simple picture was painted: you put a metal into a solution of its ions. ...
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1answer
606 views

When surface area of electrodes is increased, why does the current in the galvanic cell increase?

I did a lab in galvanic cells where I changed the surface area. As a result, the current increased, but I don't really understand why. I guessed it was because more are means that more ions from the ...
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1answer
115 views

What are the products in the reaction of sulphuric acid and Group 2 metals?

When group 2 metals, says magnesium, is reacted with nitric acid, oxide of nitrogen is produced beside hydrogen gas. The standard electrode potential values agree with this: $$ \begin{align} \ce{Mg^...
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32 views

What is the reasoning behind deriving electrode potential of a metal-metal sparingly soluble salt electrode?

Considering a sparingly soluble salt $M_xN_y$ of the metal $M$, in which the corresponding reaction is $M_xN_y$ = $xM^{y+}$ + $yN^{x-}$, the standard electrode potential is given by $E^{o}_{M_xN_y/M/...
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205 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+}(...
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1answer
280 views

Does higher Oxidation/ reduction potential translate to higher energy storage in battery?

Some articles refer to the fact that Lithium is preferred metal of choice for batteries because their half cell voltage is high (slightly above 3V) If that is the case why can't we use other metals ...
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21 views

What are the reasons that make platinum a good electrocatalyst for oxygen reduction reaction? [duplicate]

Researchers are trying to find new electrocatalysts for energy related reactions in fuel cells in order to replace the expensive platinum-based materials. I would like to know what are exactly the ...
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2answers
43 views

Where does Free Energy go in a Redox Reaction?

This doubt came to my mind while answering the following question: Why does a voltaic cell not operate unless the two separate compartments are connected by an external circuit? The answer seems ...
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3answers
400 views

No sign flipping while figuring out the emf of voltaic cell?

I learnt that for a voltaic cell, the value for the $E_\text{cell}^\circ$ when the reaction is spontaneous is given by $$E_\text{cell}^\circ = E_\text{cathode}^\circ - E_\text{anode}^\circ, \label{...
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1answer
214 views

Intensive and Extensive Properties--Resistance

Is resistance an intensive quantity or an extensive one? And why? Let me present 2 scenarios. Resistance of a wire: The resistance of a wire depends on area and length. This implies it depends on the ...
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1answer
326 views

Does electrolysis of aqueous tin(II) chloride produce Cl₂, SnCl₄ or both?

When applying a current to an aqueous solution of tin(II) chloride, tin crystals grow from the cathode. However, I'm not sure about the anode. It seems like there are two possible reactions: $$\ce{2 ...
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30 views

Oxidation states of Cu in YBa2Cu3O6 based on crystal structure [duplicate]

How does on go about this? I understand There is a +5 charge distributed on 3 copper ions. So either we have 2+, 2+ and 1+ or 3+, 1+, and 1+. Judging from the structure there are to unequivalent types ...
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1answer
61 views

Can gold cause tin or other metals to corrode?

I stumbled upon the following article while trying to identify some old RAM modules: https://www.techrepublic.com/article/quickly-identify-ram-chips-with-these-tips/ In the article, it mentions the ...