## Electromotive force (emf)

$\Delta G^{\circ} = -nFE_{cell}^{\circ}$

Matthew Tsai 2H
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Joined: Wed Sep 18, 2019 12:20 am

### Electromotive force (emf)

Can someone explain what emf is exactly and if we need to know anything about it other than that it represents max work?

Dina 2k
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Joined: Wed Sep 18, 2019 12:17 am

### Re: Electromotive force (emf)

the book mentions that EMF is the same as the cell potential of a cell.

Sanjana Borle 2K
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Joined: Fri Aug 09, 2019 12:15 am

### Re: Electromotive force (emf)

I think all we need to know is that EMF is the same thing as the cell potential, or the variable E, so if a problem refers to emf it is just referring to E.

EvanWang
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Joined: Sat Sep 07, 2019 12:16 am

### Re: Electromotive force (emf)

And also, maximum nonexpansion work is the same as Gibbs free energy, so emf directly relates to $\Delta G$

Jocelyn Thorp 1A
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### Re: Electromotive force (emf)

it's the voltage of the cell

Miriam Villarreal 1J
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Joined: Sat Aug 17, 2019 12:16 am

### Re: Electromotive force (emf)

Emf is given a positive value if the cell reaction is spontaneous. This implies that the electrode on the left forces electrons into the external circuit and the electrode on the right withdraws them

On the other hand, Emf is given a negative value if the cell reaction is nonspontaneous. This implies that if the half-cell on the right side of the shorthand cell notation is releasing electrons, making the right-hand terminal of the voltmeter negative

Sreyes_1C
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Joined: Fri Sep 28, 2018 12:19 am

### Re: Electromotive force (emf)

if its the same as cell potential I would assume we don't need to know much more about it

005384106
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Joined: Sat Aug 24, 2019 12:16 am

### Re: Electromotive force (emf)

How do you calculate for EMF?

005384106
Posts: 101
Joined: Sat Aug 24, 2019 12:16 am

### Re: Electromotive force (emf)

Why do we measure the voltage difference of two cells?

Julia Holsinger_1A
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Joined: Tue Feb 26, 2019 12:16 am

### Re: Electromotive force (emf)

005384106 wrote:Why do we measure the voltage difference of two cells?

The difference in potential voltage is what gives rise to electric current