galvanic cell; anode = - how?

[joonkimdds]

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I understand that anode is + in electrolytic cell because oxidation happens in anode and thus it loses electron.

In galvanic cell, oxidation still happens in anode and the electron moves from anode to cathode. How did anode become - if oxidation happens?

 

[polola55]

I understand that anode is + in electrolytic cell because oxidation happens in anode and thus it loses electron.

In galvanic cell, oxidation still happens in anode and the electron moves from anode to cathode. How did anode become - if oxidation happens?

joonkimdds: I got confused earlier about this thing too. The main thing that you need to know is that electrolytic and galvanic cell oxidize and reduce at the respected anode and cathode. Electrolytic cell requires an energy to become spontaneous and the opposite is true for galvanic cell. Thus, for electrolytic cell, cathode is (-), anode (+) and for galvanic cell, cathode (+) and anode is (-). If you understand this, you will be sure to not get confused again. It also took me a while to understand too.

 

[AmpedUp]

Way I remember it...

Electrolytic Cell - flow of electron from anode to the cathode end. The electron is negative and cathode is negative (kinda awkward!)

the rest is easy to figure out

beyond that, electrochemistry isn't my favorite...due to the fact we didn't spend much time on it in GChem. Wasn't my teacher's favorite subject either...

 

[redchesus]

the way I understand it is, whichever end is driving the reaction is the (-) end since these are negatively-charged particles that are moving:

in a galvanic cell, the electrons come spontaneously from the anode so it's what's driving the reaction so it's the (-) end

in an electrolytic cell, electrons are forced to the cathode from an outside source which results in reduction, which then drives the oxidation so really the cathode is driving the reaction so it's the (-) end

 

[UndergradGuy7]

The anode is the (-) terminal. I think it was named (-) just for convention because it produces a lot of electrons, so a (-) charge would build up around it. Just pretend as if the electrons haven't left yet. The negative electrons are attracted to a positive terminal (the cathode). So this makes sense.

It does get confusing since you would think the anode should be (+) since it is loses electrons and the electrons go to the cathode. But this would not make sense. Think about it if you made the anode positive and the anode also gave off electrons. Where would the electrons go? The electrons are (-) and would be attracted to a (+) terminal and would stay where they are. This does not make sense.

 

[redchesus]

The anode is the (-) terminal. I think it was named (-) just for convention because it produces a lot of electrons, so a (-) charge would build up around it. Just pretend as if the electrons haven't left yet. The negative electrons are attracted to a positive terminal (the cathode). So this makes sense.

It does get confusing since you would think the anode should be (+) since it is loses electrons and the electrons go to the cathode. But this would not make sense. Think about it if you made the anode positive and the anode also gave off electrons. Where would the electrons go? The electrons are (-) and would be attracted to a (+) terminal and would stay where they are. This does not make sense.

*Sigh* the anode is (+) and the cathode (-) in an electrolytic cell... that's the convention

 

[UndergradGuy7]

*Sigh* the anode is (+) and the cathode (-) in an electrolytic cell... that's the convention

I was talking about galvanic, where the anode is negative.