Writing Half-Reactions

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Rakhi Ratanjee 1D
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Joined: Fri Sep 29, 2017 7:04 am

Writing Half-Reactions

Postby Rakhi Ratanjee 1D » Tue Feb 20, 2018 7:26 pm

If asked to give the half-reactions of an electrochemical process, do we have to flip the anode, or do we give both equations in cathode form?

SantanaRodriguezDis1G
Posts: 56
Joined: Sat Jul 22, 2017 3:00 am

Re: Writing Half-Reactions

Postby SantanaRodriguezDis1G » Tue Feb 20, 2018 7:59 pm

cathode is reduction and anode is oxidation

Alejandra Rios 1L
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Re: Writing Half-Reactions

Postby Alejandra Rios 1L » Wed Feb 21, 2018 12:15 am

If you are not able to identify the anode and cathode then you should flip one since you need a redox reduction (containing a reduced and oxidized form)

Adrian Lim 1G
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Re: Writing Half-Reactions

Postby Adrian Lim 1G » Wed Feb 21, 2018 1:23 pm

I believe it would be better to flip the anode because in a redox reaction, we would add up the two half-reactions, so some terms would need to balance out on both sides.

Sarkis Sislyan 1D
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Re: Writing Half-Reactions

Postby Sarkis Sislyan 1D » Wed Feb 21, 2018 3:44 pm

The half-reactions given in the appendix of the textbook give the reduction reaction. Since the anode is where oxidation takes place, we would need to flip the half-reaction given in order to get the oxidation half-reaction. The cathode is where reduction takes place, so no such flipping is needed.

McKenna disc 1C
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Re: Writing Half-Reactions

Postby McKenna disc 1C » Wed Feb 21, 2018 4:13 pm

Sarkis Sislyan 1D wrote:The half-reactions given in the appendix of the textbook give the reduction reaction. Since the anode is where oxidation takes place, we would need to flip the half-reaction given in order to get the oxidation half-reaction. The cathode is where reduction takes place, so no such flipping is needed.


But still, the sign of the standard potential value doesn't need to be flipped, right? That's the part that confuses me-- the reaction at the anode needs to be flipped, but does its sign need to be switched from positive to negative or vice versa since the reaction is reversed?

Jennifer Ho 1K
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Joined: Thu Jul 13, 2017 3:00 am

Re: Writing Half-Reactions

Postby Jennifer Ho 1K » Thu Feb 22, 2018 1:00 am

Whenever you flip the half reaction you need to flip the sign of the standard potential.


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