Ecell Always Positive

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NatBrown1I
Posts: 62
Joined: Fri Sep 28, 2018 12:17 am

Ecell Always Positive

Postby NatBrown1I » Sat Mar 16, 2019 5:00 pm

In the textbook it says that Ecell is always positive in a galvanic cell. Why is that?

josephperez_2C
Posts: 70
Joined: Wed Nov 15, 2017 3:04 am

Re: Ecell Always Positive

Postby josephperez_2C » Sat Mar 16, 2019 5:03 pm

We have the equation deltaG = -nFEcell. For galvanic cells, the reaction is spontaneous and therefore Ecell must be positive because deltaG is negative. Not sure if this was a bit roundabout but that's how I think of it.

Riley Dean 2D
Posts: 60
Joined: Fri Sep 28, 2018 12:15 am

Re: Ecell Always Positive

Postby Riley Dean 2D » Sat Mar 16, 2019 9:09 pm

Is there a case where Ecell could be negative?

Danielle Hoekstra 1C
Posts: 30
Joined: Tue Oct 02, 2018 12:15 am

Re: Ecell Always Positive

Postby Danielle Hoekstra 1C » Sat Mar 16, 2019 9:13 pm

Because the E°cell value of the cathode is positive and anode is negative, the Ecell will be positive as it is equal to the cathode minus the negative anode.


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