Unanswered Questions
947 questions with no upvoted or accepted answers
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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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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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How to derive absolute temperature scale from Carnot engine?
This question is about how to obtain an absolute or thermodynamic temperature scale using a Carnot engine.
The reasoning below appears in the book "Heat and Thermodynamics" by Zemansky and ...
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1
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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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Can Gibbs Free Energy equation be used to explain why some phase changes are exothermic or endothermic?
I was wondering about some ways to explain why some phase changes are exo / endo.
I am aware that for endothermic phase changes (boiling, melting, sublimation) energy input is required to raise the ...
2
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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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Degradation via electrolysis and electrode surface area
What is the relationship between electrode surface area and processes such as electrolysis/electrode polarization?
Let's say for example I want a fixed electric field between two electrodes in a ...
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Why zinc metal in solid state has an initial tendency to lose electrons when a zinc metal strip is dipped in a zinc sulphate aqueous solution?
Let us say I dip a metallic strip of zinc in a container filled with zinc sulphate aqueous solution. On observing the changes occurring in the solution, we would find that the zinc metal present in ...
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Gibbs free energy ( condition)
I want to derive Gibbs Free Energy formula from 1st and 2nd law of thermodynamics.
I saw some texts using T and P constant in derivation. I am confused about that. If n,P, T are constant then its ...
5
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1
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How to remove glass shards out of a tiny hole to fit capillary tube?
This is oddly specific, but I am having trouble making the setup work for my electrochemical cell. We're doing Scanning Electrochemical Cell Microscopy (SECCM)* and the device has a capillary tube fit ...
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Does the relation between ΔG° and K vary based on how they are changed?
From the equation ΔG° = ΔH° - TΔS°, I have always been taught that with
+ΔH° and +ΔS°, the reaction would be favorable in cases with high temperatures and with
+ΔH° and -ΔS°, the reaction would be ...
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2
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Why does my data drift from the nernst equation at low values of Q?
I saw a similar question from last year but there were no answers and I was facing the same problem.
I designed an experiment for a nickel-nickel concentration cell where the cathode is kept at 1M and ...
2
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101
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Cyclic Voltammetry for a Capacitor - Positive Current, Potential is decreasing?
In the boxed red region, why is the potential decreasing when the current is still positive? To my understanding, when the current is still positive (i.e. not changing direction), the capacitor will ...
- 41.6k
3
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Short-circuiting an electrolytic cell with metal dendrites and observing interesting chaotic 1/f noise
While conducting home experiments on the electrolytic deposition of copper in a micro-gap (2-3 mm), under a microscope (x40) I observed interesting effects of short-circuiting by metal dendrites of ...
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1
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Entropy and Internal Energy in irreversible adiabatic process
I have a question related to title. Please see the following discussion:
In an irreversible process:
$ΔU_\mathrm{irr} = q_\mathrm{irr} + w_\mathrm{irr}$
$ΔU_\mathrm{rev} = q_\mathrm{rev} + w_\mathrm{...
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