Battery/Charge Question

[Gareth56]

If a battery doesn't supply electrons or protons to a circuit but supplies "charge" which travels from the high potential (+) side of the battery, through the circuit ( e.g. a bulb), then finally to the low (-) potential side of the battery then what is this "charge" that the battery supplies?

 

Thanks

G56

[Klaynos]

Electrons travelling -ve to +ve... It's just we define charge as being from positive to negative, which is not physically true...

[ecoli]

Current was defined as flowing from positive to negative, before we knew that the opposite was true. We didn't change the convention because the mathematics work the same way.

 

This current is indeed the movement of electrons... but there is no net gain or loss of electrons in a conductor because the number of electrons 'pumped' in by the positive terminal of a battery is the same number of electrons received by the negative terminal.

[zule]

If a battery doesn't supply electrons or protons to a circuit but supplies "charge" which travels from the high potential (+) side of the battery, through the circuit ( e.g. a bulb), then finally to the low (-) potential side of the battery then what is this "charge" that the battery supplies?

 

Thanks

G56

I don’t know about batteries. But I think that instead electrons or protons, inside the battery can be moved ions. Ions are positive charged atoms and their movement can supply electrical power.

[swansont]

Most of the electrons that are flowing in a circuit were already in the circuit. The battery gives them the energy to move in a particular direction; it doesn't contain or supply the charge that's flowing.

[YT2095]

the Charge is created by a chemical "imbalance" inside the battery itself.

one side is rick in electro positive material and the other in electro negative material.

 

these chemicals want to react to form a stable compound, and the only way it can do that is to Share electrons (the basis for all chemical reactions).

 

these electrons no necessarily need to jump from one atom to the other Directly though as they would if you just mixed them up in a test tube. but instead they can be made to travel along a wire and do some work (lighting a bulb for instance).

 

that`s Basically what is happening, hope that helps.

[Gareth56]

Thank you swansont and YT2095 for your sensible and mature replies it's appreciated. When swansont says "the Charge is created by a chemical "imbalance" inside the battery itself." what exactly is Charge? Which is the main thrust of my question.

[DrP]

Never mind. I'll see if I can get a sensible (and gown-up) answer elsewhere as clearly it's beyond the first 3 attempts.

 

Klaynos' and Ecoli's answers seem sound to me. WAW.

[YT2095]

Typically a battery cell works on a REDOX reaction (REDuction OXidation)

 

Reduction is the Gaining of electrons (Cathode or - side of the cell)

Oxidation is the Loss of electrons (Anode or + side of the cell)

 

the difference in Electrode Potential between these 2 chemical agents is what is responsible for the flow of electrons and the Voltage you get.

Current is more of a Physical aspect that relies on things like Surface area of the 2 chemical agents in close contact.

 

for example Lithium metal has an electrode potential of about 3 volts, but if the Lithium metal was only the size of a postage stamp you wouldn`t get much current out of it, but if it was like a sheet of A4 paper you`d get Plenty out (several amps) but BOTH would be 3 volts

[Gareth56]

So are you saying [YT2095] that the high electric potential terminal (the +)of a battery produces electrons, due to chemical reactions within the battery(the electrochemical cell) which are then sent around the circuit?

[YT2095]

a Reducing agent becomes Oxidised in the reaction, that means that the reducing agent has lost an electron.

 

the Oxidising agent in the battery becomes Reduced and thus Gains electrons.

 

it`s that movement of electrons that gives you the charge.

 

this will continue until a balance is reached and there`s no oxidiser or reducer left to react and you`r left with a stable and fully reacted compound. we call this a Flat battery.

[Edtharan]

what exactly is Charge?

Charge (in terms of a battery) is the amount of energy contained by the imbalance between the two sides of the battery. One side is trying to draw electrons to it (the positive or "+" side) and the other is trying to push electrons away form it (the negative or "-" side).

[Gareth56]

In College Physics (Wilson & Buffa) it states the following:-

 

"Chemical processes involving the electrolyte and two unlike metal electrodes cause ions of both metals to dissolve into solution. Since they dissolve at different rates, and thus leave different excess electrons behind, one electrode (the cathode) becomes more negatively charged than the other (the anode). Thus the anode is at a higher potential than the cathode."

 

Why is the anode (fewer electrons) at a higher potential than the cathode when the cathode contains more electrons? I would have thought that the electrode with the greater number of electrons would have been at the higher potential.

[YT2095]

yes I can see your "Logic", but you must think of it in terms like a pair of scales or even a see-saw.

the More electrons it has it will tip the ballance and so it has enough of a "Vote" to Pull the electrons from a material that has least "vote", or in the case of a see-saw you put 7 marbles on one side and 1 on the other the 7 will go down and the 1 will roll down towards it.

 

the "Magic number" is 8 in Chemistry, all compounds like to be Stable like the Noble gases with an 8 outer electron count, this is the aim of any chemical reaction.

sometimes it doesn`t always become 8 but it will do it`s best or at least Next best to do this.

[DrP]

 

Why is the anode (fewer electrons) at a higher potential than the cathode when the cathode contains more electrons? I would have thought that the electrode with the greater number of electrons would have been at the higher potential.

 

 

The first 2 posts by (the ones you dissed) explain this correctly.

 

QUOTE :

"Current was defined as flowing from positive to negative, before we knew that the opposite was true. We didn't change the convention because the mathematics work the same way. "

[YT2095]

DrP, Nice avatar

 

I`m glad you liked it!

[DrP]

Cool! I hope you don't mind me nicking it for a while!?

 

I hope I havn't been too rude to Gareth here.. Am I right about this?

[YT2095]

yeah, not a problem, by all means use it

 

as for Garreth I can`t comment, that`s His place to do so, not mine.

I will say however that although the first 2 posts are Correct in what they say, they don`t address the question that was asked.

 

in Fact I`m not entirely sure I`v done a good job of this myself?

[DrP]

Admittedly they do not explain what charge is and don't answer the origional question. They are correct in what they say though and do explain the confusion between positive and negative being the wrong way round.

[Gareth56]

The explanation of charge is I think complete, thanks.

 

I'm still a tad confused regarding the question "does a battery produce electrons at the negative terminal"? Yes or No. If Yes do these electrons therefore flow from the negative terminal of a battery to the positive terminal despite the following:

"The direction of an electric current is by convention the direction in which a positive charge would move. Thus, the current in the external circuit is directed away from the positive terminal and toward the negative terminal of the battery. Electrons would actually move through the wires in the opposite direction."

[YT2095]

the electrons move from the Negative side to the Positive side, the Electron has a Negative charge.

this is what happens in Reality.

 

Why they claim otherwise in Physics is beyond me also???

[Gareth56]

"does a battery produce electrons at the negative terminal"?

[YT2095]

Yes.

[Gareth56]

Thank you YT2095. So electrons are produced at the negative terminal (via redox half reaction) and travel through the external circuit to the positive terminal which has an excess of positive charge (again via redox reactions in that half cell).

 

Meanwhile the conventional current is defined as the flow of positive charge from the positive terminal through the circuit to the negative terminal.

 

Would that be a fair description?

[insane_alien]

yes. that would be a fair description though in reality no electrons are produced, just shuffled around in an interesting manner.