reversing reaction  [ENDORSED]

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katherinemurk 2B
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reversing reaction

Postby katherinemurk 2B » Mon Feb 25, 2019 4:26 pm

how come for some of the homework problems in the solutions manual they reverse the reaction. What is the significance of this?

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Re: reversing reaction  [ENDORSED]

Postby Chem_Mod » Mon Feb 25, 2019 4:38 pm

There are two methods that you can use:

1) E(cell) = E(cathode) - E(anode)
E values represent the reduction potential. For your anode, oxidation occurs, so the the total energy of the cell is found by the above equation.

2) Write out all the half reactions, explicitly. You can "reverse" one of the reactions so that oxidation is occurring in one, and reduction in the other. When you reverse the reaction, you also switch the sign of E. You can sum these E value up to find the E of the total cell.

Shubham Rai 2C
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Re: reversing reaction

Postby Shubham Rai 2C » Mon Feb 25, 2019 4:40 pm

One of the half reactions has to be reversed in order to balance the number of electrons on both sides of the overall reaction.

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Re: reversing reaction

Postby marisaimbroane1J » Mon Feb 25, 2019 4:48 pm

In a Galvanic cell, you will always have a reduction and oxidation reaction. The Ecell values in the table are only for reduction reactions, so you need to reverse the reaction for oxidation. This will allow you to balance the equation as well as get the correct sign of the oxidation reaction E value.

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