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### Cathode and Anode

Posted: Thu Mar 05, 2020 6:34 pm
Why can we assume the cell can do work when the E value at the Cathode is bigger than the E value at the Anode?

### Re: Cathode and Anode

Posted: Thu Mar 05, 2020 6:40 pm
A cell can do work whenever Ecell > 0. This will always be the case if the Cathode is greater than the Anode.

### Re: Cathode and Anode

Posted: Thu Mar 05, 2020 7:05 pm
Equilibrium not reached so it will continue if cathode Ecell greater than 0.

### Re: Cathode and Anode

Posted: Sat Mar 07, 2020 10:02 pm
The work done by the cell is is equal to the change in gibbs free energy. Based on the equation deltaG=-nFE, E needs to be positive so that energy is released (deltaG is negative) and thus the cell does work.

### Re: Cathode and Anode

Posted: Sun Mar 08, 2020 3:51 am
Well for an E cell to do work its value has to positive. To find the value for cell potential it would be Ecathode - Eanode and so if cathode is larger then it will yield a positive value.

### Re: Cathode and Anode

Posted: Sun Mar 08, 2020 9:28 am
My TA mentioned that E cell can be negative sometimes and I believe there is a question with a negative E cell in section 6N.

### Re: Cathode and Anode

Posted: Sun Mar 08, 2020 10:55 am
E(cell) = E(cathode) - E(anode); since we want E(cell) > 0, E(cathode) > E(anode)

### Re: Cathode and Anode

Posted: Sun Mar 08, 2020 1:09 pm
What does the cathode and the anode do?

### Re: Cathode and Anode

Posted: Sun Mar 08, 2020 1:17 pm
Is the left side is the anode that dissolves, what happens to the right side (cathode)?

### Re: Cathode and Anode

Posted: Sun Mar 08, 2020 1:54 pm
From the equation deltaG = -nFE, you can tell that a reaction is spontaneous and does work if the value of Ecell > 0. Since to find E you would subtract the potential of the cathode by the potential of the anode, you will always get Ecell > 0 if the cathode value is larger.

### Re: Cathode and Anode

Posted: Sun Mar 08, 2020 3:06 pm
Electrons travel from cathode to anode, so cathode>anode means work is done.

### Re: Cathode and Anode

Posted: Sun Mar 08, 2020 9:57 pm
The cell will continue to do work until it dies. So E has to be positive.

### Re: Cathode and Anode

Posted: Sun Mar 08, 2020 10:00 pm
A cell can do work when Ecell is greater than zero, meaning that the cathode must be greater than the anode.

### Re: Cathode and Anode

Posted: Sun Mar 08, 2020 11:24 pm
It is just standard convention that we travel from the anode to the cathode. When a cell is working spontaneously and naturally, then it will always travel from left to right.

### Re: Cathode and Anode

Posted: Sun Mar 08, 2020 11:31 pm
Because if there is still potential difference between the cathode and anode, then the reaction is not at equilibrium, and electrons will continue to flow from the cathode to the anode. This generates electricity.

### Re: Cathode and Anode

Posted: Sun Mar 08, 2020 11:36 pm
This is because the Evalue at the cathode basically determines if the Ecell will be positive or negative. When the value is positive the system can do work, when the value is negative work must be done on the system. The equation is Ecell=Ecath-Eannode, so if Ecath>Eanode, the equation will have a net positive value.

### Re: Cathode and Anode

Posted: Tue Mar 17, 2020 9:35 pm
We want the ECell to be positive in order to do work because once the Ecell is equal to zero then that is when the battery is considered to be "dead."