cathode vs anode

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Athena L 1B
Posts: 59
Joined: Fri Sep 28, 2018 12:18 am

cathode vs anode

Postby Athena L 1B » Thu Feb 28, 2019 5:05 pm

When you are given something like H+ and H2 with Ni2+ and Ni, how do you know which pair is the cathode and which is the anode?

Lauren Ho 2E
Posts: 70
Joined: Tue Oct 09, 2018 12:16 am

Re: cathode vs anode

Postby Lauren Ho 2E » Thu Feb 28, 2019 5:08 pm

You can determine the cathode reaction and anode reaction by seeing which combination would cause you to end up with a greater voltage when the two reactions are combined

EllaBerry
Posts: 68
Joined: Fri Sep 28, 2018 12:29 am

Re: cathode vs anode

Postby EllaBerry » Thu Feb 28, 2019 6:16 pm

The Ecell must be positive, and so you use the Ecathode -Eanode equation to determine which reaction is the cathode and anode by looking at the values you get when you put the E of one reaction in the cathode place and the other in the anode place. If the value is positive, the place you have the E values in are correct and you can look at the corresponding reactions to see which is cathode and which is anode.

Carissa Young 1K
Posts: 65
Joined: Fri Sep 28, 2018 12:17 am

Re: cathode vs anode

Postby Carissa Young 1K » Thu Feb 28, 2019 7:05 pm

whichever half-rxn is oxidized (loses e-, oxidation number incr) is the anode and the half-rxn that is reduced (gain e-, oxidation number decr) is the cathode

Jerome Mercado 2J
Posts: 60
Joined: Tue Nov 28, 2017 3:02 am

Re: cathode vs anode

Postby Jerome Mercado 2J » Thu Feb 28, 2019 7:25 pm

Note if Ecell is negative that means it is the opposite notation. So either flip the sign of Ecell and flip the notation as well if given a negative Ecell.


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