Questions tagged [electrochemistry]

Electrochemistry is the branch of physical chemistry that studies the relationship between electricity, as a measurable and quantitative phenomenon, and identifiable chemical change, with either electricity considered an outcome of a particular chemical change or vice versa. These reactions involve electric charges moving between electrodes and an electrolyte (or ionic species in a solution).

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Ni-Cd Battery discharge circuit model

I am struggling with deriving a set of equations to represent mathematical model of Ni-Cd battery, so would you give me a through explanation and proper textbook/reference articles.
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What is the difference between ionic conductivity and electrical conductivity in an electrolyte?

If we apply an AC current to a conductor it creates an associated alternating magnetic field around it. That's the theory. Additionally, when a current passes through the conductor, there is some ...
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Electrical resistance of sodium chloride solutions with varying temperature

I am doing an experiment where if I try to increase the temperature of the sodium chloride solution I have and then measure resistance, I would expect that the resistance will increase as there are ...
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About a battery's positive terminal

Does the positive terminal of the battery mean that the concentration of electrons is more there. In some places people say that current moves from positive to negative and they call it a convention ...
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What causes water to be non-ohmic?

Its been a while since I posted here about what I have been trying to find out regarding resistance of water at high voltages. I may seem oddly obsessed with this, but it is forming a big part of a ...
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Pressure Drop as a Predictor of Degree of Electrochemical Machining?

I'm trying to get my head around the concept of electrochemical machining and if it would be possible to measure the pressure drop across a pipe as the process is ongoing at a given flow rate to ...
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How water affects the resistance of a material at different voltages?

as I said before in recent science projects I have been studying the effect of water on the electrical resistance of materials that absorb water such as wood and sponge (the reason for the majority of ...
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How electrolytes conducts electricity?

While studying electrochemistry, I came across two key points that I'm unable to understand. why does DC alone break down the electrolytic liquid and b) Why doesn't AC do the same?
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Force on a test charge inside a cell

Considering test charge inside a cell. Let the cell be in an open circuit. I know that a potential difference will develop between the two electrodes of the cell. If I take a test charge and place it ...
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Can chemical energy be related to average charge separation within molecules?

On another thread, a chemical battery was described as a "charge separating factory" (Battery as charge separating factory), which got me thinking about what happens inside a battery at the ...
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Is tap water an ohmic conductor?

Earlier today, I asked a question regarding why I was getting weird resistance readings and based on responses which I am thankful for concluded it could possibly be the electrolysis, the fact i ...
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What happens to resistance of tap water as voltage is increased?

In recent days I have done a few experiments measuring the current of water as it goes up from 9 volts up to 36 volts, and following Ohms law to convert it to resistance. And I discovered a very ...
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In electrochemical sensing, why do molecules binding cause changes in current?

From my limited understanding in electrochemistry, a set of electrodes are biased at a given potential and when there is a chemical reaction(antibody-antigen binding for example), a subsequent change ...
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Does current flow inside a battery?

When connected in a circuit, does current flow inside a battery. If yes, in which direction?
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Is the heat produced at a catalyst related to the amount of charge transferred to the electrochemical reaction?

Let us say you have a catalyst which drives a reaction taking in or removing electrons. Obviously, the electron transport itself is inefficient and will result in heat loss. My question: is this heat ...
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What causes the potential difference in a half-cell?

This question pertains to the subject of electrochemistry --specifically a half-cell and not a full galvanic cell. From what I understand, a half-cell has a potential of its own. This is voltage is ...
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What is the need for reference electrode?

An absolute electric potential of a point is simply not defined. Only the difference between two points is defined and can be measured,so we are forced to take a reference point's potential. Electrode ...
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Maxwell relation for battery undergoing reaction

I am trying to solve Reif Problem 5.16, and seem to continue to run into a barrier. I here give the problem and solution from the solution manual, as well as my work. This is not a homework question. ...
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What causes the flow of electrons from anode to cathode in a Daniell cell?

In a standard galvanic cell, I understand that electrons flow from the anode to the cathode. For example, in a Daniell cell, electrons flow from the Zn anode to the Cu cathode. Before the two half-...
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Electrolysis of a solution of $\rm Ni(NO_3)_2$

This is a problem given in my textbook A current of $3.7 amp$ is passed for 6 hours between inert electrodes in 0.5 litres of 2M solution of $\rm Ni(NO_3)_2$. What will be molarity of the solution ...
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What causes the electric field in a Daniell Cell?

I would like to know what causes the e-field in a Daniell cell. From a chemistry point of view, I do understand that this is initiated by a redox reaction in which Gibbs free energy is decreased. The ...
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Why does electrolytic conductance increase with dilution?

We are only talking about strong electrolytes. According to my book, conductance increases slightly due to dilution. Explanation given by my book: On the one hand, in a dilute solution, the number of ...
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What is the cross-section area of an electrode when measuring electrolytic conductivity?

If we have two flat plates, then the area is understood easily. However, if our two electrodes are like this: then will we take the area of $S_1$ or $S_2$?
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Is the positive terminal of a Daniell cell positively charged electrostatically?

Suppose, the circuit is open. I understood from @Dale's answer that the negative terminal of the battery is indeed electrostatically negatively charged. Suppose, it can have a charge of $-0.5C$. ...
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What's the highest theoretical energy density in a chemical battery?

Is there a theoretical limit to how energy dense chemical batteries can be? How can one calculate them? And what stops us from reaching those limits?
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If a battery (cell) was elongated, will it have higher voltage?

Voltage is the potential difference between the terminals of the battery,and this potential difference is created by the work that the chemicals inside the battery had done. Also, work done is ...
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Battery efficiency [closed]

I have 4000 mah 4 cell and a 5000 mah 3 cell Which battery is more efficient. Higher mah or more number of cell. I am selecting batteries for rc plane
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How does a cell discharge their voltage?

I'm posting this question because I haven't been able to find any sources on the internet to make sense of. The statement I am working with is as follows: The terminal potential difference of a ...
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Is battery a source of electrons OR a driving force?

A more elaborate question " With my previous knowledge I am aware that a wire possesses a sea of electrons ( free electrons) and the flow of those electrons is called current . The energy to flow ...
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Tokamak and Lithium "blankets"

I am working on planning out nuclear fusion for a fictional world, and I am wondering if two ideas are able to work together, or if they contradict each other. So Dueterium-Tritium fusion releases ...
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Where do electrons flow inside a battery? What happens inside a battery?

Sorry, if this sounds silly, but I have had this doubt from a long time. Please help me, I'll forever be grateful to you. I'm a student of 10th grade. This is my doubt: What happens when electrons ...
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Can a PEM fuel cell be converted into a PAFC or High Temperature-PEM fuel cell?

My goal is to use methane to generate electricity using a fuel cell stack! The electrolyte a typical PEM fuel cell would get carbon monoxide poisoning if methane was used. I've read that Methane works ...
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Potential difference in circuit of dry cell [duplicate]

I referred to this question potential difference but had a few doubts as to why do electrons move in a circuit? What exactly causes them to do so? And what is the chemical reaction in the cell which ...
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Why does current flow in an electrolytic cell?

Many explanations of current flow in electrolytic cells will state that electrons flow from the external power source into the cell (via the cathode). But surely this current flow would stop if there ...
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Is the reason why a normal battery ran out of "juice" that it has reached electrostatic equilibrium between its two terminals?

If we connect a normal battery to a load circuit, its stored electric potential energy on its two terminals (+) & (-) will be consumed by work done on the load and eventually the battery is "...
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Time-reversal in a simple current loop

In classical physics, time and velocity change sign under time-reversal while position, acceleration and force do not. An accelerating particle going to the right becomes a decelerating particle going ...
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Does charged Li-on battery burn more than discharged one if damaged? [closed]

I am wandering if a charged Li-on battery burns more than discharged one if damaged, considering that the charged one has more energy in it. Thanks.
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How long does it take for a battery to begin to produce a current after it is shorted? [duplicate]

From the moment you short a battery, how long before the current BEGINS to flow. Does a virtual photon need to travel the path of the wire? I was thinking it would be the length of the wire divided by ...
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Electrons produced in water by ionizing radiation vs. electrons due to electrostatic charge: are they equally reactive?

It is known that one of the things generated in water or aqueous solutions by the ionizing radiations are free electrons that quickly become "hydrated" or "aqueous electrons" (see ...
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How to increase the current in a lemon battery?

I tried to make the classic lemon battery today and ran into a bit of trouble. I used 4 large tennis ball sized lemons with copper and zinc galvanized nails for electrodes. I connected the 4 lemons in ...
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What are the electrons doing? Voltage of two batteries in a series

I've been trying to visualise what is going on inside the batteries when you connect, let's say two 1 and 5 V batteries, and why the voltage is added to 3 V. Several good explanations have tried to ...
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How batteries create voltage?

I am trying to have a more fundamental understanding of electricity and specifically what voltage is. My memory of highschool physics was that a battery has an excess of electron on one terminal, and ...
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Connect negative terminal of a battery to Earth

I have a question about what happens in following experiment: Assume we have a battery with two Galvanic half cell, eg a magnesium and a copper cell. Since copper has higher electrode potential that ...
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If ions are stable, then why does a battery have an expiration date?

I am talking about non-rechargable batteries. As far as I understand, ions in a battery are stable form of atoms, just having excess electrons, or lesser electrons (relative to the neutral atom). Now ...
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Direction of current detected by ammeter for ions

if the pipe contains Na+ and Cl- ions, will the ammeter have the reading as $enAV_{Na}$+$enAV_{Cl}$ or $enAV_{Na}$-$enAV_{Cl}$ (as the ions move in opposite directions?)
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What is the highest possible battery reaction voltage?

For a battery cell with the overall chemical reaction $xA + R = A_xR$ (where x is the number of mols of A that reacts per mol of R), (Huggins 2008) defines the Maximum Theoretical Specific Energy (...
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How Does Electrical Work Change Internal Energy of the System?

I know this stack exchange may not be the most appropriate to ask this question and it is better to ask it at chemistry stack exchange. However, I got no satisfying answers there so I figured I'll ...
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What does a battery produce? Is it Electric Potential Difference (EPD) or Electro Motive Force (EMF)?

I have read a lot of posts about Electro Motive Force, Electric Potential Difference and their differences, but I still confused. What I know is that EMF produces a EPD and keeps it constant, then ...
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Why does the potential across the terminals of battery increase on moving from negative terminal to positive terminal?

I really want to know that how does battery create a potential difference across the circuit. When we cross the battery from its negative terminal to positive terminal the potential rises by the ...
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Why the electric field inside the battery (when connected to a circuit) opposes the electric field into the wire?

I mean yea, ok, it makes sense inside the battery to point from + to -, but what the physical meaning of being opposite to the current flow (or the E-field inside the wire) is? For the sake of ...
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