Eºcell

[Mohamed Mido]

So my understanding is that the reaction in a Galvanic Cell is spontaneous when the value for Eºcell is positive. Am I correct in this? and also can Eºcell ever be a negative value?

[Abby Lam 3F]

I think you're right that positive E cell naught is spontaneous and negative E cell naught is not spontaneous. We have been solving for a positive E because we want a spontaneous answer, but I'm pretty sure negative E values exist.

[Emerald Wong 1B]

Yes, when Eºcell is positive, the reaction is spontaneous. The value must be positive in galvanic cells, but it can be negative in electrolytic cells

[Sabina House 2A]

If the reaction is under standard conditions and the Eº of the cell is positive, the reaction is spontaneous. However, the Eº of the cell can be positive but if the cell is not under standard conditions, such as a really high concentration of the products, then the reaction may not be spontaneous, even with a positive Eº. This is because the E cell value is different than the Eº value of the cell when the cell isn't under standard conditions. Yes, the Eº cell can be negative but the cell would not be spontaneous.

[Annie Liang 3D]

You're correct that a galvanic cell is spontaneous when Eº cell is positive. The Eº cell can be negative for an electrolytic cell, which is why an electrolytic cell requires a power source to run the reaction.

[emwoodc]

Yes! you are correct :). When E cells are positive, the reaction is spontaneous.

[Ryan Laureano 3I]

To add on think about the equation delta g naught = -nFE naught. For a spontaneous reaction (delta g naught is negative) E naught has to be positive.

[Ava Nickman]

yup! you are right

[VincentLe_3A]

Yes, when E naught Cell is positive, then the reaction is spontaneous.

[Kyla Roche 2K]

When E cell is positive the voltage is positive. Also, when G is negative this makes Ecell positive which is helpful in understanding why -G means spontaneous.

[LarisaAssadourian2K]

That's correct! When E naught is positive, the reaction is spontaneous, and when it's negative, it is not spontaneous. Also, there are negative E naught values, but for a galvanic cell, it must be positive.

[Sydney Sullivan 2J]

Just wanted to add that this concept is covered in question #14 on the week 7/8 sapling assignment!