Calculating standard potential of cell

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Emily Huang 1E
Posts: 30
Joined: Fri Sep 28, 2018 12:20 am

Calculating standard potential of cell

Postby Emily Huang 1E » Tue Feb 26, 2019 6:47 pm

Do you switch the sign of standard E, (cell potential), when you reverse a reaction or does the sign remain the same?

Joanna Pham - 2D
Posts: 113
Joined: Fri Apr 06, 2018 11:04 am

Re: Calculating standard potential of cell

Postby Joanna Pham - 2D » Tue Feb 26, 2019 7:48 pm

When you switch the reaction, the standard potential sign is reversed.

However, it is important to note that if you multiply an entire chemical equation by a number, you DO NOT multiple the standard potential by that number. You only that for standard gibb free energy of the reaction. For example if you have Zn + CU2+ -> Zn2+ + Cu (standard potential = 1.10 V and standard gibbs = -212 kJ ) and you multiply the equation by 2 to get 2Zn + 2CU2+ -> 2Zn2+ + 2Cu, then the standard potential remains as 1.10 V but standard gibbs increases to -424 kJ.

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