# Tagged Questions

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### How pseudocapacitors work?

I have read that pseudocapacitors are combined of a carbon electrode and a metal oxide one. On the carbon electrode simply a double layer is built up and on the other some chemical actions(redox) ...
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### Is it possible to transform chemical energy in electrical energy by modifying the equilibrium constant?

Considering a Daniell cell, is it possible to create endlessly electrical energy by using atmospheric temperature (for example) variations to modify the reaction's equilibrium constant ? I apologize ...
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### Can we isolate the iron ions in a solution?

I was wondering if it was possible to isolate the iron ions in a soltion without adding anything (to precipitate for example). Maybe using a magnetic field? Thanks
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### Circuit theory paradox - Unexpected results [closed]

I recently studied capacitors and found out that there is something called 'ideal circuit paradox'. Searching Google I found that one can cannot find the potential difference between two points in a ...
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### Is a real voltaic cell always schematically equivalent to an ideal battery and a resistor?

In the diagram I have attached, the top circuit is the schematic equivalent I am trying to use to model the middle circuit which uses real voltaic cells (that have internal resistance). I am not sure ...
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### Hydrogen pressure in fuel cell

It takes energy to compress hydrogen tot 350 or 700 bar. Can some of this compression energy be recovered in the fuel cell? Higher pressure of Hydrogen leads to and increased open cell voltage n the ...
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### Ion Mobility Versus Temperature Explanation

Ion mobility versus temperature in an electrolyte seems to look like a graph that looks like an upside down curve. Now at low temperatures, I expect that the amount of energy required to move ...
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### Fuel cell HHV vs LHV

I am calculating the maximum efficiency for a fuel cell, based on both HHV and LHV. For hydrogen and oxygen in a PEMFC I calculated these at STP as 82.9% (based on HHV) and 94.5% (based on LHV). I do ...
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### Rydberg and electrical energy

I am a high school student. This year I learned the Rydberg constant and its use of finding energy of an electron in chemistry, besides in physics I learned to calculate the energies of two loaded ...
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### What material used in soil based microbial fuel?

I have seen from wikipedia that there are soil based microbial fuel which need only anode and cathode while soil itself could act as proton exchange filter But what kind of other material it needed? ...
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### Why x-axis E field exist in Electroosmosis Example

The explanation in Wiki said it is because the surface charge will induce electrical double layer at top and bottom surface, so that if we apply x direction E field, there will be a flow between two ...
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### Galvanic cell of zinc half cell and copper half cell

Where do the $Zn^{+2}$ ions come from in a $Zn$-half cell, if from zinc metal then why doesn't after some time $Zn$ metal is completely vanished and what is the purpose of $Zn^{+2}$ ions of zinc ...
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### Is sea water more conductive than pure water because “electrical current is transported by the ions in solution”?

Apparently, electrical charge is transported by the ions dissolved in water, is this true?
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### Electricity, and Gases

Electricity can be conducted by an ionic compound dissolved in water, and when it is a liquid. Can a gaseous ionic compound conduct electricity as well? A metal cab conduct electricity when it is ...
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### How to calculate ion lithium battery voltage?

I have raw data from cyclic voltammetry test of ion-lithium battery. But I need nominal voltage or Open Circuit Voltge (OCV), like is reported in the literature. But I only have Voltage (V) vs ...
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### Where can I find information on gas discharge tube mixes beyond the noble gases?

I have seen plenty of information on the noble gases, and oxygen and nitrogen. I haven't found much on other gases, or mixtures of gases. I don't really know where to look beyond google. I am in ...
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### How does calblock (water softener) work?

This "calblock" device claims to prevent limescale accumulation on water heaters in a washing machine. It sits between the water faucet and the washing machine; the water passes through it. I cannot ...
12k views

### Can a saltwater solution conduct electricity forever? [closed]

We know that very pure water does not conduct electricity, but salt water is a decent conductor. This is commonly explained by saying that "the ions carry the current through the solution", an ...
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### Rearrangement of oil due to high voltage electric field

I've been working on a problem for some time now and I can't figure out why exactly this happens, and I've been looking for some insight. The phenomenon can be seen in this video. We can see that the ...
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### What is the different between Poisson Nernst–Planck and Poisson Navier–Stokes in the Electrolyte?

I am now studying about electroosmosis flow phenomena which is governing by the Navier-Stokes equation and Poisson equation. By combine these two equation we can describe the electrolyte flow velocity ...
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### Why do electric pickles only glow at one end?

The electric pickle is often used as an example of a non-ohmic resistor. In the experiment, electric current excites the sodium ions inside pickle, producing very bright and intense light effect. What ...
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### Cu/Zn in salt water voltaic cell peculiar behavior — any explanation?

I was playing with my eight-year old son and his new 'lemon battery' kit -- it has 4 Copper plates, 4 zinc plates, a red LED, and pieces of wire hooked together. Having no lemons handy, I decided to ...
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### How can a fruit be used as a battery cell?

Fresh fruits can be used as batteries for glowing bulbs, but how this is possible? I mean how can electric charges flow through fruits? Do they contain chemicals like cells?
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### Chemical Potential, Boltzmann

The electrochemical potential of an ion i in an electrolytic solvent is given by: \begin{align}\mu_i(\vec r) &= \mu_i^0 + RT \ln(a_i(\vec r))\\& = \mu_i^0 + RT \ln(\gamma_i(\vec r) c_i(\vec r)...
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### Pseudo-Perpetual Motion Machine

Clearly, the Second Law of Thermodynamics precludes the existence of any theoretical device that would continue running throughout the lifetime of the universe. However, is it possible to construct a ...
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### Could a Kelvin Probe Force Microscope, in principal, be used as a voltmeter?

This question goes into the very nature of the work function that the Kelvin Probe Force Microscope (KPFM) measures. https://en.wikipedia.org/wiki/Kelvin_probe_force_microscope Let's say, you have a ...
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### Why does connecting a battery's positive terminal to the negative terminal of another battery not create a short circuit?

This is a question regarding the physics behind the observation. I have guessed the answer to the question, but I may be wrong, so I want to wait for the responses before posting it. Some major ...
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### Physical distribution of salt anions and cations during electrophoresis

If I have a volume of $L$ liters of salt water at a concentration of $\approx N$ mM NaCl and I pour it into an electrophoretic apparatus (like this one: ). Once we turn the apparatus on, and set the ...
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### Electrical Resistance and chemistry

Can some one describe or explain what happens when too much current is passed through lets say a copper wire, I am looking for an explanation to do with physics and chemistry. For instance we have ...
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### What will happen when lightning strikes on the surface of the deep sea?

The lightning is having enormous amount of energy, as it strikes the ground it makes various electrical and magnetic effects. If the lightning strikes a tree, that will be burst by lightning. ...
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### Do batteries provide electrons

In chemistry, the reaction at negative electrode produces electrons,which flow to the positive electrode through the circuit. But then, if circuit has a conductor, then wouldn't it also release ...
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### Why does Li+ ion move to cathode in Li-ion battery?

when Li-ion battery is discharged or being used, the positive lithium (Li+) ions move from anode to cathode through the electrolyte. Meanwhile the electrons move in the same direction through the ...
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### What's causing the effect of salt in voltage arcs?

I just came across this video demonstrating that salt increases length of voltage arcs. There is no explanation which leaves me quite confused. Does the salt decompose during the process?
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### Can you derive reaction rates from the potential difference across a battery?

There were several cases where I was able to (relatively easily) derive potentials for interactions in my statistical mechanics course. I know that there is no real way to derive the kinetics of a ...
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### Confusion about conduction of electricity in a solution

I'm trying to unserstannd conduction of electricity in a solution. Is it correct that anions give their extra electrons to the anode, which transfers the electrons to the cathode, where the cations ...
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### Can antiprotons make stable bounds with halogens?

Halogens are known for being highly electronegative. That means their electron dipole moment are high enough that they want to share other atoms electrons. I'm wondering If two Halogen atoms could ...
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### Can we extract chemical energy remotely?

To state directly. Can we use any electromagnetic method to extract energy from fat? Humanity store useless fat inside their body. And to work out mechanically leads to frustration of tireness and ,...
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### Freezing or melting Brine

In the freezing of brine, is it possible to do it at a rater or in such a way that the water only freezes or the ice is somehow isolated? Or conversely is this possible in the melting of brine-ice?
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### I have got some weird data after a homemade battery experiment

Okay, so i've been searching for some time, for perpetual motion machines of the second kind. So things got into my mind, such as this homemade solar cell. And i thought in my mind:" It's not the ...
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### Solving for the Nernst Potential in 3D

Hi guys I'm totally stuck on the following question: We know the ionic flux between two chambers due to uneven concentration can be computed by the Nernst-Planck equation j = -D_p \left(\nabla C ...
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### Fitting two semicircles in a Nyquist plot? [closed]

I have done some impedance spectroscopy fist time recently and got the following [Nyquist plot](http://en.wikipedia.org/
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### Why do batteries work?

Consider diagram A. In diagram A a car is at the top of a cliff. Gravity is pulling it down, but it does't move since its on a flat surface. Even though it would be at a lower potential at point B, it ...
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### How does a battery work?

How does the positive terminal of the battery attract electrons? Does the electric field emitted by the positive terminal attract the electrons?
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### Why is it that the cathodic battery symbol in an equivalent battery circuit doesn't point in reverse for an open circuit case?

I've been thinking about batteries a whole lot, and I've uncovered why the battery symbol looks like a pair of cap-like things in circuit diagrams: it's modeled as two cap-like things using an ...
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### How does Passivation in Mercury-arc-valve cause “diode” behavior

Does passivation of lead anodes cause them to become semiconductors? Or even become diodes (eg. a p-n passage)? How does this work on an atomar level? This question has been risen by trying to ...
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### Could a strong AC electric field adversely affect the capacity of a lithium battery?

I run some battery powered test equipment in close proximity (~10cm) to a conductor carrying 25kV (50Hz AC). I find the battery life is much shorter than expected, having checked the current ...
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### Question on static electricity & electron transfer

Static electricity is caused by the transfer of electrons between substances right? For example, take a balloon and your hair. Both are stable and electrically neutral. So why would electrons jump ...
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### Is there any reproducible tested evidence for Ni-H cold fusion?

The main replications of cold fusion, the ones that are beyond reproach, used Pd/d as the system. But commercial developers have often claim to use Ni-H to achieve similar effects. The claims include ...