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22 votes
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True or false: "A used AA battery contains fewer moles of electrons than a new AA battery."

Very bad explanation in the email response. The explanation reads.. "Thus, the battery has the same number of protons and neutrons, but less electrons. This also means more unreactive metal ...
AChem's user avatar
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21 votes

Does chemistry change under high voltage?

Long story short, no, they don't. Charging a vessel to 1 MV is not a big deal, if you look at it from the inside. To put things into perspective, imagine a vessel of about 10 cm across, which is ...
Ivan Neretin's user avatar
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10 votes
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What is the optimal voltage for storing a 3.7 V lithium polymer battery?

The $\pu{3.6-3.8 V}$ range is a good general choice, but it may be battery-specific. The particular voltage for 40% charge may differ for different cell technologies, e.g. various deviations of ...
Poutnik's user avatar
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8 votes
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Could a lead-acid battery electrolyte be replaced by hydrochloric or nitric acid?

In the lead battery it is very important that the electrodes transform into insoluble lead sulfate when discharged, especially at the cathode where lead(IV) oxide is turning into lead(II) sulfate. ...
Stapke's user avatar
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8 votes

Why does it so long for a Lithium-ion battery to be charged from 98% to 100%?

The short answer is: The ending stage uses much smaller charging current, so it lasts longer. TCharging of any cell in the contant voltage mode, not limited to lithium cells, leads to asymptotically ...
Poutnik's user avatar
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7 votes

Are there ionic solids that conduct electricity?

Yes. Another example is VO2. Over 67 °C its crystal structure changes to rutile with a band gap of ~0.1 eV. Dopants of other substances can reduce the temperature at which it becomes a conductor.
Jelly Strawberry's user avatar
7 votes

True or false: "A used AA battery contains fewer moles of electrons than a new AA battery."

Your professor is wrong, and you can prove it. According to your "professor": As a battery is used, through the flow of electrons, electrons are lost to the environment ... Those electrons ...
Bohemian's user avatar
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6 votes
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Why did my lemon and penny battery fail?

By not removing every last trace of copper from the sanded-side of the pennies, I created a kind of short-circuit that discouraged the charges from moving through the stack of pennies. This is the ...
hBy2Py's user avatar
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6 votes
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Do electrons truly flow in circuit?

The key here is the concept of metallic bonding. or, the sharing of electrons between metal atoms like those in a copper wire (a typical conductor). In this type of atomic bond, electrons no longer ...
E. Hunter's user avatar
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6 votes
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Why is AC current used rather than DC current for calculating the conductance of a solution(see body)?

When a current is passed through an electrolyte, a chemical reaction takes place. This alters the composition of the solution over time and you won't actually be measuring the conductivity(or ...
Govind Balaji S's user avatar
6 votes
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Are there ionic solids that conduct electricity?

Yes, there are. Ionic conductivity greatly varies between compounds. For some of them is much higher then for others. They are called fast ion conductors, or superionic conductors. Well known ...
Mithoron's user avatar
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6 votes

What metals are safe to use as electrodes when doing electrolysis of water (I am trying to produce hydrogen gas)

Magnesium sulfate is not the best choice when carrying out an electrolysis. Because, near the cathode, the solution becomes basic, and magnesium hydroxide $\ce{Mg(OH)2}$ will be produced, and it is ...
Maurice's user avatar
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6 votes

Why aren’t electrolyzers made like this(two inter-locking coils)?

The geometrical arrangement for galvanic cells and electrolytic cells is usually very different. The spiral arrangement is routinely used for the former, but not the latter. For the electrolytic cells,...
Poutnik's user avatar
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5 votes
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What is the underlying chemistry behind the triboelectric effect?

You would've probably heard of the commonly given example, rubbing a glass rod with silk. The glass rod becomes positively charged, and the silk becomes negatively charged. But why? That's your ...
Pritt says Reinstate Monica's user avatar
5 votes

Do plasma globes generate ozone?

Image Citation: Volkov, Alexander & S, Hairston & Patel, Darayas & Sarkisov, Sergey. (2023). Cold Atmospheric Pressure Plasma Jet and Plasma Lamp Interaction with Plants: ...
Ronith's user avatar
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5 votes
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Amperage for the electrolysis of water?

In electrochemistry, the rate of electrolysis depends on rate of charge entering the cell. Second most important point is that one can either control potential or current but not both during ...
AChem's user avatar
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5 votes
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Would laying an atom thick piezoelectric material near a heat source generate current?

tldr: not quite, but there are a lot of interesting applications You're correct that a piezoelectric material interconverts mechanical energy into electrical energy. Importantly, there's both: direct ...
Geoff Hutchison's user avatar
5 votes
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Open-circuit potential of an electrochemical cell

Basically you've have the right ideas. The open-circuit potential of an electrochemical cell is the theoretical voltage that one would measure as the current flow approaches zero. Think of plotting ...
MaxW's user avatar
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5 votes
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Is Li2CuSb thermoelectric?

Just about any two conductors can produce thermoelectricity. Some pairs produce only a tiny voltage difference, such as platinum/rhodium-alloy thermocouples, which is very inefficient at generating ...
DrMoishe Pippik's user avatar
4 votes
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What are the ideal pair of (everyday) elements to pair in a thermocouple

My book has a few metals/alloys listed in a Seebeck Thermoelectric Series: Antimony, Nichrome, Iron, Zinc, Copper, Gold, Silver, Lead, Aluminum, Mercury, Platinum-Rhodium, Platinum, Nickel, ...
Pritt says Reinstate Monica's user avatar
4 votes

Why is a silent electric discharge used for the preparation of ozone from oxygen?

As the Gibbs energy (G) for the reaction is highly positive , it is made sure that ozone does not decompose back to give oxygen and nascent oxygen and that's why silent electric discharge is used.
user7658311's user avatar
4 votes
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Why is a silent electric discharge used for the preparation of ozone from oxygen?

According to this Wikipedia article: Dielectric-barrier discharge (DBD) is the electrical discharge between two electrodes separated by an insulating dielectric barrier. Originally called silent (...
airhuff's user avatar
  • 17.5k
4 votes

Why do gases under low pressure conduct electricity?

The cathode ray tube doesn't conduct electricity per se. It liberates free electrons that are simply moving through a vacuum from one end to the other. In practice, you can't create a real vacuum, so ...
Zhe's user avatar
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4 votes

Placing oxygen molecule into electric field

Yes, an oxygen molecule (much like any other molecule) can be broken by electric field alone. No, it won't be broken into separate oxygen atoms, precisely because the atoms are neutral and the bond ...
Ivan Neretin's user avatar
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4 votes
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Formation of Bands in Semi-Conductors

doesn't explain why electrons in the conduction band are able to conduct electricity while electrons in the valence band can't Electrons in the valence band can conduct electricity, as long as the ...
orthocresol's user avatar
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4 votes

Why won't removing the salt bridge cause the battery to recharge?

The ions in the salt bridge never leave the salt bridge. That's not true. The ions literally have to move to balance the charge of the gain / loss of the electrons at the electrodes. (You even ...
Van's user avatar
  • 311
4 votes

How exactly are ions in a Mass Spectrometer accelerated?

The acceleration of the freshly generated ions is stepwise (similar to a linear particle accelerator), i.e. the beam of ions is guided an array of electrodes with a small opening in their centre, as ...
Buttonwood's user avatar
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4 votes
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If two atoms "fight over" one electron, who will win?

If two atoms of different elements are both missing exactly one electron in their valence shell so that they have a charge of +1 and we place an electron between them, exactly in the middle. There ...
StephenG - Help Ukraine's user avatar
4 votes
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Why the DMM (multimeter) register negative resistance when measure a drop of hydrochloric acid

The multimeter probe tips are dissolving and setting up a galvanic cell that augments the current flow thru the ohmmeter. The probe tips may be of the same metal, but the ohmmeter voltage will favor ...
James Gaidis's user avatar
4 votes

What is the safest way to hook up car battery jump cables and why?

Many recommended procedures such as this one call for connecting (+) to (+), then (-) on the "good" battery to a metal component in the "dead" car engine. The negative terminal of the battery is ...
Oscar Lanzi's user avatar
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