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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What is going on in this electroplating experiment?
So we were asked to conduct an electroplating experiment involving copper coil and nickel coin. The nickel coin served as the negatively charged terminal (due to bubbles being formed on its surface), ...
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Does cooling a phone in a fridge or freezer damage the battery (lithium-ion battery)?
I saw a fair amount of Reddit and Quora posts on whether cooling a phone in a fridge or freezer damage the lithium-ion battery but they give contradictory answers without any evidence or scientific ...
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regarding units of $\Delta G$ = -nFE
Does the $\Delta G$ in this formula have units of energy/mol or simply energy (e.g., kcal or kJ)?
Is the number of electrons transferred "n" unitless?
My impression is that in this formula $\...
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How does complex formation help in uniform deposition during electroplating?
Question 17 on the National Standard Examination in Chemistry (2003-04), India, asks:
In the gold plating process, sodium cyanide solution is used as an electrolyte instead of nitric acid, because:
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Why is usually Tafel extrapolation done and not a fit of the Butler Volmer equation
Good day guys,
I have noticed in many papers and books there is mention of the use of the tafel approximation to determine the charge transfer coefficients and exchange current density.
Where, for ...
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Understanding the hydrogen chemical potential in transition-metal oxide redox
Recently I've been reading a paper by Ceder & coworkers about the stability of various manganese hydroxide phases under constant pH and electrode potential. In this paper, the authors derived a so-...
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Cell without salt bridge nor porous surface - ions in same aqueous solution - What's the name reference of these cells?
I've seen an unusual type of cell, where the main reaction is $A_{(s)}+B_{(s)} = A^+_{(aq)}+B^-_{(aq)}$, on a YouTube seminar on electrochemistry presented by Geoff McConohy.
The cell has the ...
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Examples of lamellar microstructure growth driven by ion replacement
Let me present an analogy between:
The well-known directed lamellar microstructure formed from an eutectic melt by cooling.
An unknown (to me, so far) but probably possible lamellar microstructure ...
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Nonzero voltage between identical electrodes in water
I placed two identical electrodes inside a recipient filled with tap water and measured a nonzero voltage with a DC component that started around - 30 mV and continued changing until reaching -40 mV. ...
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Limitation of bipolar ion exchange membrane
I have been recently using bipolar membrane in my project. However, I discovered a problem is that potassium ion seems leaking through the bipolar membrane and pass to the other side which only ...
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Prediction of reduction potential behavior in amalgam
In this link, the research and comparison have been made for metal and metal amalgam reduction potential. There are some behavior that I could conclude:
Strongly reducing metal such as lithium , ...
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Coating a nickel foam with mm poresize with zinc
I'm currently trying to coat a nickel Foam (NF) 1 cm thickness with high loadings and homogenous plating of Zn metal. The main concern right now is that the outer most areas like corners and edges get ...
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Please explain the difference between HFC technology and PEMFC technology
I understand how hydrogen fuel cells (HFCs) function, but what are the differences between them and PEMFC's?
I know that there are HT-PEMFCs and LT-PEMFCs, for low and high temperatures.
Do PEMFCs ...
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How is energy in an electrochemical cell (e.g Daniell cell) conserved?
I wonder how energy is conserved in an electrochemical cell? A search did not provide a satisfactory answer.
In an electrochemical cell you put in some chemicals and their chemical energy is converted ...
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Work in an electrochemical system
Good day guys,
I was looking at Bard's book on Electrochemical Methods, in Chapter two the change in Gibbs energy for a reaction is given by:
$$\Delta G = -nFE_{rxn}$$
This explanation is consistent ...
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Electrons Transferred in an Electrochemical Reation
I was reading Bard's book, I noticed in Chpt 2, he defines the change in Gibbs free energy of a cell as:
$$\Delta G = nFE_{rxn}$$
He describes $n$ as the number of electrons, and $F$ as having units ...
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Gibbs energy and maximum obtainable work
What I've understood about the change in Gibbs energy for a physical process (e.g. isothermal expansion of a gas) is that it's a measure of the maximum obtainable non pV work. I also suppose that this ...
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Blue spots and pink spots during rusting experiment with potassium hecacyanoferrate (III) solution and phenolphthalein
I'm referring to the rusting experiment where an iron nail is coiled with a metal that either has a less positive/more negative E⁰ value or more positive/less negative E⁰ value then iron, and is then ...
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Gibbs free energy change for cells at different temperatures
Why is $\Delta G=\Delta G^o+RT\ln Q?$
The standard proof states $\Delta G = V \Delta P - S\Delta T$ and T is constant so $\Delta G = V \Delta P$ . Till now I understand but after that the ideal gas ...
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Electrochemical Cell? Metal at anode and salt at cathode
Per suggestion, complete rewrite with more details:
I no longer believe this is electrochemical migration.
There is a lot of information on:
Galvanic cells with two half-cells and a salt bridge
...
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Why reversible potential of water oxidation is reported as 1.23 V and not -1.23V?
The standard Gibbs free energy of formation for water is -237 kJ/mol, the $\Delta G^\circ$ for the opposite reaction (water splitting) is 237 kJ/mol (non-spontaneous). If we use this value to ...
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What happens if a proton conductor electrode is used for electrolysis of tris(cyclopentadienyl)lanthanum?
To attempt a deposition of $\ce{La}$ thin films inside a conductive organogel electrode, let's consider the following setup:
There are two liquids in two cells, separated by a proton conductive wall: ...
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Electroetching Stainless Steel
I attempted to electroetch some stainless steel with sodium chloride. The solution became very turbid as something was falling out of solution. I believe I was consuming the electrolyte and making ...
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Is electroplating possible in a solvent that doesn't dissociate precursor molecules?
There are metalorganic compounds, soluble in nonpolar solvents without dissociation into ions. Is it possible, in some rare cases, to apply voltage to submerged electrodes so that it causes the ...
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How does oxidation state truly track the loss and gain of electrons?
In the book Chemical Principles: The Quest for Insight (7th ed.) by Peter Atkins and Loretta Jones, it's stated that chemists assign an "oxidation number" to each element to keep track of ...
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Why can you not electroplate paper?
Not to completely plate paper with gold, but enough to give it a hue. In this question, How to best to electroplate paper money? the comments said it could not be done. Why?
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What makes Raney Nickel so effective as a catalyst in alkaline fuel cells?
I've been reading extensively about alkaline fuel cells (AFC). One of the key points that has been highlighted is that AFCs can either use Raney Nickel or Platinum as a Catalyst. Wikipedia lists a ...
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Enthalpy of electrochemical redox half reactions with O2, H2 and H2O
I am working with numerical analysis of solid oxide fuel cells. In such systems we have an oxidation reaction taking place in the anode, and a reduction reaction taking place in the cathode.
Oxidation:...
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Can Advanced Oxidative Processes (AOPs) destroy nitrates and phosphates?
I am currently working on a science project about treating agricultural wastewater and the subsequent eutrophication that occurs.
I was wondering if Advanced Oxidative Processes (AOPs) could destroy ...
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Is this normal in an electrolyzer?
I made a dry cell electrolyzer using graphite foil. I hoping for minimal corrosion, but only after some time of running, the both the anodes and cathodes are destroyed. Picture at the bottom. Does ...
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Standard electrode potential from thermodynamic data
I am looking for a reference where the values of standard electrode potentials of simple reactions calculated from the heat of submilation, energy of ionization, energy of hydration and possibly other ...
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Will the product of electrolysis of all dilute aqueous solutions be hydrogen or oxygen?
According to my book, the electrolysis of some dilute solutions give hydrogen and oxygen because the concentration of other elements is very low. So, does this apply to all dilute solutions?
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Why does molar conductivity of strong electrolyte increases on decreasing the concentration i.e. by doing dilution [duplicate]
My teacher first told me that strong electrolytes form more ions
cause they dissociate completely so if we increase the concentration then more ions will be formed and hence conductivity will be more.
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Sodium increase in saltwater chlorination swimming pools [closed]
If I understand well the chemistry of a saltwater swimming pool (I’m not a chemist), over years, we add salt in the swimming pool. This is due to the fact that in Salt water chlorination, Chlorine gas ...
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What could be causing these random, pseudo-blister defects when electroplating galvannealed steel?
We are getting these small, random, almost pseudo-blister defects when trying to electroplate 1mm thick galvannealed steel. It is occurring about 20% of the time. The rest of the part looks fine but ...
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Multiple rate-determining steps and rate expression
I am trying to understand the concept of the rate laws governing hydrogen evolution of platinum. More specifically, I am trying to understand the multiple occurrence of a rds to the overall rate law ...
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Sensible Enthalpy vs Enthalpy (at standard reference states)
I am reading a book (Thermodynamics an Engineering approach), I am reading over the section of steady-flow systems with chemical reactions.
The book just introduced the following formula for the ...
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Automate electrolysis for hydrogen generation via humidity
I have been having an idea regarding the methodology used for electrolysis.
In practice, for electrolysis to occur at all, there needs to be an electrolyte present. This electrolyte generally would ...
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How is the amount of electrolyte per kilowatt in a Molten Carbonate Fuel Cell calculated?
While searching for Molten Carboante Fuel Cells I notice that quite a lot of them are really big, for example, this 250 kilowatt MCFC is the size of a truck.
Asking "why it is that big" can'...
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How do manganese nodules in the ocean sustain oxygen production without depleting over geological time scales?
The news reports that manganese nodules on the ocean floor produce oxygen through electrochemical reactions. But how do these nodules sustain themselves without depleting? Do they replenish their ...
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Calculate the solubility product of calomel (Hg2Cl2) using potential? [duplicate]
How do you calculate the solubility product of calomel if the potential of the calomel electrode (Hg2Cl2 / Hg / KCl) is given against a standard hydrogen cell with E = 3.22 V. A 1M KCl solution was ...
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Calculate the solubility product of calomel using potential?
How do you calculate the solubility product of calomel if the potential of the calomel electrode (Hg2Cl2 / Hg / KCl) is given against a standard hydrogen cell with E = 3.22 V. A 1M KCl solution was ...
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Variation of Molar Conductivity [duplicate]
Consider 10 moles of X dissolved in 1 L solution, molarity 10M, and volume occupied by 1 mole of X is $\pu{100 cm3}$, so molar conductivity of X is $k\times\pu{100cm^3}$, k being conductivity. So on ...
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Are there any advantages to using potassium ion over lithium ion batteries?
Are there any advantages to using potassium ion batteries over lithium ion batteries? What properties make an alkaline metal an ideal alkaline-ion battery?
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pH probe equation derivation
This is a bit of a niche question, but I am struggling to find a good answer just by Googling around. I've been reading recently into the function of pH probes and ion-selective electrodes in general.
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Limiting current vs Steady-state limiting current
I have been reading on the concept of limiting current.
In books, the mass-transfer limiting current is given by,
$$ i_L = \frac{nFADC^*}{\delta}$$
Often the Cottrell equation is introduced.
However, ...
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Correct interpretation of Impedance: IR-Drop and Nyquist plots
Good day guys,
I have been lately studying impedance and IR drop in electrochemical systems.
From my readings I have come across different interpretations.
According to my books, from the Nyquist plot:...
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Does the cathode always attain a positive charge or is it just a convention?
Suppose I have a galvanic cell composed of two half cells, one containing Zinc electrode dipped in an electrolytic solution (say of ZnSO4) while the another one having Lithium electrode dipped in ...
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Iodine/iodide electrochemistry help
I have an electrochemistry experiment with iodine in solution.
I am initially wanting to quantify the iodide in solution and extrapolate the concentration of I2(aq) and I3-(aq) in solution from this ...
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Irreversible uncharged acid/base indicator
I am conducting a process in an electrochemical cell where at the cathode or anode surface the pH might be acidic or basic. To figure out if either one is correct I would like to find a reaction that ...
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