Why do we flip E for oxidation?

Posts: 100
Joined: Sat Jul 20, 2019 12:15 am

Why do we flip E for oxidation?

I know that E is given, however, why do we need to flip the sign when we are trying to use the E for oxidation?

Tracy Tolentino_2E
Posts: 140
Joined: Sat Sep 07, 2019 12:17 am

Re: Why do we flip E for oxidation?

Because all the E potentials are given as reduction values. You have to flip this value to get the oxidation value.

Zoya Mulji 1K
Posts: 105
Joined: Thu Jul 11, 2019 12:15 am

Re: Why do we flip E for oxidation?

If you are just using the cathode - anode equation you don't need to flip any numbers because the minus sign takes care of that. But, if you are using the method of writing out the half reactions and making the net equation, you'll have to make sure you flip the E for the oxidation half reaction.

TarynD_1I
Posts: 100
Joined: Sat Aug 24, 2019 12:17 am

Re: Why do we flip E for oxidation?

If using the equation E(cell) = E(cathode) - E(anode) and using reduction values found in the appendix or on the sheet he will give us on the test, then I'm pretty sure that there is no need to flip the anode cell potential value when accounting for oxidation. In this case you would not need to change the sign from Ecell given for standard reduction.

Niharika 1H
Posts: 50
Joined: Thu Jul 25, 2019 12:16 am

Re: Why do we flip E for oxidation?

In the appendix, the equations are given as reductions. So, for the E for oxidation, we flip the reaction and change the sign of E.

Andrew F 2L
Posts: 103
Joined: Sat Aug 17, 2019 12:17 am

Re: Why do we flip E for oxidation?

What I found was confusing was that in Youtube videos, the teachers would be adding the cell potentials while the book has us subtract the anode from the cathode. These are both the same thing it is just that, like others have said, you don't change the standard potential sign when you are using the subtraction method.

ABombino_2J
Posts: 102
Joined: Thu Jul 11, 2019 12:15 am

Re: Why do we flip E for oxidation?

You are only supposed to flip E when you are given reduction potentials and you are looking for oxidation potentials. This is almost all the time becase our appendix gives reduction potentials.

Deena Doan 2F
Posts: 100
Joined: Sat Aug 17, 2019 12:17 am

Re: Why do we flip E for oxidation?

Since it is given in cell potential, that means that it is a reduction. So, to get oxidation, you flip it.

Posts: 100
Joined: Sat Jul 20, 2019 12:15 am

Re: Why do we flip E for oxidation?

Will we always be given E for reduction? Is that just common convention or will there be a time when we get oxidation?

Gerald Bernal1I
Posts: 102
Joined: Thu Jul 11, 2019 12:16 am

Re: Why do we flip E for oxidation?

You do not flip the sign if you are calculating the standard cell potential for the anode value.

Hussain Chharawalla 1G
Posts: 100
Joined: Sat Jul 20, 2019 12:15 am

Re: Why do we flip E for oxidation?

Be careful that if you are using the formula Ecell= Ecathode- Eanode then you would NOT change the sign

Eugene Chung 3F
Posts: 142
Joined: Wed Nov 15, 2017 3:03 am

Re: Why do we flip E for oxidation?

Cindy Adiwidjaja 1B wrote:I know that E is given, however, why do we need to flip the sign when we are trying to use the E for oxidation?

Honestly, for me, I feel like it's easier to do Cathode-anode, that way you don't have to worry about changing the E value given.

Ryan_K_1K
Posts: 51
Joined: Wed Nov 14, 2018 12:18 am

Re: Why do we flip E for oxidation?

flipping E simply changes it from reduction to oxidation

Brandon Valafar
Posts: 112
Joined: Sat Aug 17, 2019 12:16 am
Been upvoted: 1 time

Re: Why do we flip E for oxidation?

You flip E for oxidation because all the E values are given for reduction reactions. Therefore to flip the reactions to oxidation you have to also flip the E.