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Spontaneity

Posted: Fri Feb 21, 2020 1:37 pm
by 905373636
Do higher cell potentials within a cell indicate anything about the rate of the reaction or just the spontaneity?

Re: Spontaneity

Posted: Fri Feb 21, 2020 1:45 pm
by Ronak Naik
Higher cell potentials will indicate a greater level of spontaneity; however, spontaneity is a thermodynamic concept. It does not relate to kinetics, and thus, will not tell us anything about the speed of a reaction.

Re: Spontaneity

Posted: Fri Feb 21, 2020 10:48 pm
by Chris Tai 1B
Spontaneous processes don't necessarily happen quickly, it just means that over time there is a tendency for that reaction to occur.
The equation that relates spontaneity to the cell potential difference is deltaGknot = -nFEknot. This makes sense, because the more positive the E value of cell potential is, the battery is able to convert more energy to do electrical/chemical work, and because there is a negative sign, the value of deltaGknot will be more negative. Hence, the reaction as a whole will be more negative, and have a spontaneous nature. The opposite is true if the value of E is negative.

Re: Spontaneity

Posted: Sun Feb 23, 2020 7:56 pm
by DHavo_1E
Chris Tai 1B wrote:Spontaneous processes don't necessarily happen quickly, it just means that over time there is a tendency for that reaction to occur.
The equation that relates spontaneity to the cell potential difference is deltaGknot = -nFEknot. This makes sense, because the more positive the E value of cell potential is, the battery is able to convert more energy to do electrical/chemical work, and because there is a negative sign, the value of deltaGknot will be more negative. Hence, the reaction as a whole will be more negative, and have a spontaneous nature. The opposite is true if the value of E is negative.


Hello,

What does it mean when E is positive or negative? Thank you!

Re: Spontaneity

Posted: Sun Feb 23, 2020 7:58 pm
by Angela Wu-2H
Ronak Naik wrote:Higher cell potentials will indicate a greater level of spontaneity; however, spontaneity is a thermodynamic concept. It does not relate to kinetics, and thus, will not tell us anything about the speed of a reaction.


So then what tells us about the speed of a reaction? Is it just a catalyst?

Re: Spontaneity

Posted: Sun Feb 23, 2020 8:13 pm
by 305385703
Cell potential has nothing to do with reaction speed, although there are other factors that can speed up a reaction with a large cell potential. Think of it as the distance in energy between the products and reactants.

Re: Spontaneity

Posted: Sun Feb 23, 2020 8:39 pm
by VLi_2B
DHavo_1E wrote:
Chris Tai 1B wrote:Spontaneous processes don't necessarily happen quickly, it just means that over time there is a tendency for that reaction to occur.
The equation that relates spontaneity to the cell potential difference is deltaGknot = -nFEknot. This makes sense, because the more positive the E value of cell potential is, the battery is able to convert more energy to do electrical/chemical work, and because there is a negative sign, the value of deltaGknot will be more negative. Hence, the reaction as a whole will be more negative, and have a spontaneous nature. The opposite is true if the value of E is negative.


Hello,

What does it mean when E is positive or negative? Thank you!


If an electrode potential is negative that means it's donating electrons. If the electrode potential is positive it means that it is taking electrons.

Re: Spontaneity

Posted: Mon Mar 02, 2020 1:09 pm
by Chris Tai 1B
DHavo_1E wrote:
Chris Tai 1B wrote:Spontaneous processes don't necessarily happen quickly, it just means that over time there is a tendency for that reaction to occur.
The equation that relates spontaneity to the cell potential difference is deltaGknot = -nFEknot. This makes sense, because the more positive the E value of cell potential is, the battery is able to convert more energy to do electrical/chemical work, and because there is a negative sign, the value of deltaGknot will be more negative. Hence, the reaction as a whole will be more negative, and have a spontaneous nature. The opposite is true if the value of E is negative.


Hello,

What does it mean when E is positive or negative? Thank you!


If E is a positive value, then there is a positive difference in cell potential, which means there's potential for the cell to do work. This phenomenon is favorable, and indicates that it is likey that electrons will flow in a redox reaction. If E is a negative value, then the opposite is true.