# Tag Info

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To quote a source as you also noted: Copper hydroxide Cu(OH)2 is metastable. It easily transforms into copper oxide CuO more stable, either in the solid state by a thermal dehydration or at room temperature, in aqueous basic solutions. In the solid state, the transformation is performed at a relatively low temperature, 423 K. In the current case, a basic ...

3

I think the point that you're missing is that $\ce{Fe2O3}$ is never formed when there is $\ce{Zn}$ in the system. When the metal gets oxidized, the electrons come from the $\ce{Zn}$, not from the $\ce{Fe}$. This is true even if the physical location of the oxidation is on the iron, since the $\ce{Fe}$ and $\ce{Zn}$ are connected and conductive, so all of the ...

-2

Let's discuss the problem in a qualitative way. In such a cell, the metal will get dissolved in the right-hand side of the cell, where the concentration is low, so that $[M^{z+}]$ increases in this compartment, which becomes the anode. In the left-hand side, the ions $[M^{z+}]$ are discharged and deposited as a metal layer on the electrode, which is the ...

0

You are mixing two areas, electrode kinetics and electrode thermodynamics. If we have 3 apples and 2 oranges, this is not equal to 5 oranges or 5 apples but there are 5 fruits in total. Electrode thermodynamics tells you a "yes" or "no" answer in the sense that it is saying the reaction is spontaneous or not. Electrode kinetics tells you how fast the ...

2

We know, $$\lambda_c = \frac{(\text{Specific Conductivity})}{1000 \times c}$$ $$\alpha\lambda_\infty = \lambda_c$$ (where $c$ is concentration in moles per litres of the electrolyte and $\alpha$ is degree of dissociation of the electrolyte) $\lambda_{\infty}$ of water (the electrolyte) is the sum of $\lambda_{\infty}$ of $\ce{H+}$ and $\ce{OH-}$. From ...

2

It is a very good questions from a student who seems to be thinking deeply. I have been thinking to write on this topic for the last 7-8 years. In short the poles of the batteries are electrostatically charged and one can actually "sense" this charge with the help of sensitive electroscopes which were known in the time of Volta. The label anode or cathode ...

-1

An anode is the place where oxidation occurs. In a galvanic cell, like the Daniell cell ($Zn - Cu$), the $Zn$ is oxidized at the Minus pole. $Zn$ is oxidized into $Zn^{2+}$ ion and the electrons are sent in the electric connexion going to the $Cu$ electrode. $Zn$ is the anode (negative sign) and $Cu$ is the cathode (positive sign) If the same setup is used ...

0

Here are my comments on the associated chemistry not usually discussed in presentations of the Daniell cell (see, for example, this overly simple rendition). The electrochemistry starts with a divided galvanic cell with the zinc displacing the copper metal from the aqueous CuSO4 (see prior reference for half-cell reactions). Importantly, the concentrated ...

0

If you plate the pieces with zinc or silver, the main source of zinc/silver in the ground coffee will be from abrasion between the parts and the coffee beans and not from chemical attack. A few milligrams of zinc or silver (or iron for that matter) won't to do any harm to your health, specially if diluted in many coffee cups along several months or years. ...

0

What you are measuring is not the potential $Fe^{2+}/Fe^{3+}$. It is the potentiel of the couple $[Fe(CN)_6]^{4-}/[Fe(CN)_6]^{3-}$ which is equal to +0.36 V in the table.

0

Note that the formal potential of a redox reaction $E=- nF \Delta G$ and the measurable electrode potential are 2 different things. You change the sign of the former when reverting the equation, but you cannot change the sign of the latter. The electrode keeps just one sign and the reaction occurs there in both directions. E.g. the potential of $\ce{Zn/... 0 Good question. The short answer is just throw the numbers into the equation. In all other thermodynamic equations, everything is "added," and if there are subtractions, it comes from the fact that values themselves are negative. In this case, technically, the potential for the reaction of chromium is +0.74 V (because it is the reverse reaction of the ... 0 As others have answered, yes the potential of the cell will still change. It sounds like you're looking for a more "physics-y" answer than the ones provided so here goes. The Nernst equation (and equilibrium equations in general) work based on concentration and not total moles. To understand why, start with a homogeneous reaction, like$\ce{HCl + NaOH <-&...

0

Technically you are correct. The thermodynamic potential of electrolyte decomposition should not be affected by the electrode composition. which just influences kinetics, not thermodynamics. The word "just" here is doing way more work than you're giving it credit for. There are situation where the kinetics of electrolyte decomposition are so slow that ...

2

Firstly, I would replace the word "feasible" with "favorable". I'm also going to replace $E_{cell}$ with $E_{OCV}$, where the open circuit voltage (OCV) is the potential of the cell without any applied electric potential. So you're right in that if the $E_{OCV}$ is positive, the net reaction is thermodynamically favorable: it will occur spontaneously if ...

0

In an electrochemical cell, increasing the concentration of reactants will increase the voltage difference, as you have indicated. A higher concentration of reactant allows more reactions in the forward direction so it reacts faster, and the result is observed as a higher voltage. If you have adjusted the cell volume to keep the total amount of reactants ...

2

The primary problem is too low permeability = too high resistence of the gloves, causing high voltage drop where it should be minimal one. The gloves are not hydrophilic enough for electrolyte soaking to get low resistance. The remaining voltage - after subtracting the glove voltage drop - is not high enough to cause electrolysis by significant current. ...

1

the background limits ‘are the potentials where the cathodic and anodic currents start to flow at a working electrode when it is immersed in a solution containing only an electrolyte added to decrease the solution resistance (a supporting electrolyte). Bard's book is notoriously complex. Some bright scientists are not good at communication. Richard Feynman ...

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