Electron Movement in a Closed Circuit: How Do Batteries Facilitate the Flow?

[ghost99]

Here's my question. On a closed circuit, you have the electrons of the conductor being pushed-pulled around the circuit from the negative end of the battery to the positive end.

So what happens to the electrons when they reach the positive end of the battery?
In order for the electrons to move around the complete circuit, don't they have to go through the negative end of the battery? If so, how can do this if the excess electrons would repel them?

 

[Dale]

So what happens to the electrons when they reach the positive end of the battery?

They are consumed in the redox reaction at the cathode.

 

[ghost99]

I guess that's where my confusion comes from.

I thought that the electrons moving in a circuit all came from the conductor (i.e the battery does not supply the electrons just the voltage). So the same electrons just moved around the conductor as the voltage was being applied. Is this correct?

 

[Integral]

I guess that's where my confusion comes from.

I thought that the electrons moving in a circuit all came from the conductor (i.e the battery does not supply the electrons just the voltage). So the same electrons just moved around the conductor as the voltage was being applied. Is this correct?

No, the battery produces electrons. Why do you think a D cell is so much bigger then a AAA? It has more reactants thus can produce more electrons, but has the same voltage.

 

[ghost99]

ok
The battery produces electrons, but is it only to produce the voltage?

Or are you saying these electrons the the battery creates are moved through the conductor also?

 

[Dale]

Do you understand redox reactions? If you write down the reduction and oxidation half reactions reactions separately you will see that on one side the metal loses electrons and ions to the electrolyte and on the other side electrons and ions in the electrolyte are deposited onto the metal.

 

[mrspeedybob]

In a nutshell...

1. A chemical reaction at the cathode between the cathode and the electrolyte deposits an electron on the cathode and produces a positive ion in the electrolyte.

2. The electron flows through the circuit. At the same time the ion moves through the electrolyte to the anode.

3. A second chemical reaction occurs at the anode that combines electrons with positive ions to form neutral molecules.

During steps 1 and 3 the chemical composition of the cathode, anode, and electrolyte are all changed. As the amount of reactive material drops the rate of the reactions also drops. When the rate of reaction no longer meets the demands of the circuit the battery is dead.

 

[ghost99]

Is the reactive material the electorlyte? or the anode/cathode material?

 

[Dale]

Yes. They are all reactive materials.