Anode and Cathode

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Khoa Tran 2B
Posts: 12
Joined: Fri Sep 25, 2015 3:00 am

Anode and Cathode

Postby Khoa Tran 2B » Sun Feb 07, 2016 9:40 pm

How do we know which one is anode or which one is cathode if both half reactions have their electrons on the reactant ?

AliceBarrington4c
Posts: 18
Joined: Fri Sep 25, 2015 3:00 am

Re: Anode and Cathode

Postby AliceBarrington4c » Sun Feb 07, 2016 9:54 pm

When the electrons are both on the reactant side, you flip the reaction that has the lowest cell potential, and make the cell potential negative. from this point you can balance the half reactions and write the full cell reaction.

Crystal Ma
Posts: 9
Joined: Fri Sep 25, 2015 3:00 am

Re: Anode and Cathode

Postby Crystal Ma » Sun Feb 07, 2016 11:49 pm

The reactant in the reaction that has the lower cell potential will give out electron in the whole electrochemical reaction (aka being oxidized), and become the anode.

huanglejun
Posts: 13
Joined: Fri Sep 25, 2015 3:00 am

Re: Anode and Cathode

Postby huanglejun » Mon Feb 08, 2016 9:11 pm

We should flip the half equation that has lower standard electric potential and if the reaction is favorable, the standard electric potential of the cell should be positive and the standard Gibbs free energy should be negative.


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