Test 2 on Standard Cell Potential

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Philip
Posts: 100
Joined: Sat Sep 07, 2019 12:16 am

Test 2 on Standard Cell Potential

Postby Philip » Sat Mar 14, 2020 9:03 am

The half-reactions are
Ce 4+ (aq) + e- = Ce 3+ (aq) Standard E = 1.44V
Li+ (aq) + e- = Li (s)

How do I know which one is the cathode and which one is the anode for me to use standard E cell = standard E cathode - standard E anode????

Philip
Posts: 100
Joined: Sat Sep 07, 2019 12:16 am

Re: Test 2 on Standard Cell Potential

Postby Philip » Sat Mar 14, 2020 9:04 am

Also I need to find the standard Gibbs Free Energy, do I just use -nFE(standard)?

Justin Seok 2A
Posts: 104
Joined: Sat Aug 24, 2019 12:15 am

Re: Test 2 on Standard Cell Potential

Postby Justin Seok 2A » Sat Mar 14, 2020 9:37 am

For standard Gibbs Energy, you just use -nFE. And for knowing which one is the cathode and anode, you have to know the standard E values for both so you can determine which one is lower and thus the anode.

Philip
Posts: 100
Joined: Sat Sep 07, 2019 12:16 am

Re: Test 2 on Standard Cell Potential

Postby Philip » Sat Mar 14, 2020 2:05 pm

Oops the Lithium half-reaction has standard E = -3.040V

CNourian2H
Posts: 106
Joined: Fri Aug 30, 2019 12:16 am

Re: Test 2 on Standard Cell Potential

Postby CNourian2H » Sat Mar 14, 2020 2:08 pm

Ya, so since Ecell is more negative for the lithium equation, the anode is lithium equation.

Esha Chawla 2E
Posts: 108
Joined: Thu Jul 25, 2019 12:17 am

Re: Test 2 on Standard Cell Potential

Postby Esha Chawla 2E » Sat Mar 14, 2020 2:22 pm

Philip wrote:The half-reactions are
Ce 4+ (aq) + e- = Ce 3+ (aq) Standard E = 1.44V
Li+ (aq) + e- = Li (s)

How do I know which one is the cathode and which one is the anode for me to use standard E cell = standard E cathode - standard E anode????


To determine which one is cathode and one which is anode, you have to be given the standard E values for both reactions. Whichever one has the more positive Standard E will be reduced, and the other one will be oxidized. Then, you can determine what the Standard E of the reaction will be.

Once you have determined the Standard E, you can plug it into delta G = -nFE to determine what the Gibbs Free Energy is.

205154661_Dis2J
Posts: 109
Joined: Wed Sep 18, 2019 12:21 am

Re: Test 2 on Standard Cell Potential

Postby 205154661_Dis2J » Sat Mar 14, 2020 4:15 pm

To determine which rxn is your anode or cathode, remember that your highest Ecell would be your cathode and your lowest one would be your anode. Then when determining Gibbs free energy, you would use -nFE in order to figure it out.


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