## Concentration Cells

$E_{cell} = E_{cell}^{\circ}-\frac{RT}{nF}\ln Q$

Daniel Chen 2L
Posts: 101
Joined: Fri Aug 30, 2019 12:15 am

### Concentration Cells

Can someone explain to me how concentration cells are different from the regular galvanic cells we learned about in class? Also, why is the standard cell potential 0 in these types of cells?

Wilson 2E
Posts: 100
Joined: Sat Aug 17, 2019 12:18 am

### Re: Concentration Cells

I think the primary difference between concentration cells and galvanic cells is that the aqueous solution and the electrodes are the same, just in difference concentrations. In this case, the cell potential isn't coming from the difference in standard potentials for the electrodes, but rather the difference in concentration.
The standard cell potential is 0 since both electrodes are the same.

Owen-Koetters-4I
Posts: 50
Joined: Fri Sep 28, 2018 12:16 am

### Re: Concentration Cells

in a concentration cell the two electrodes have the same composition but different compositions. By measuring Ecell the concentration of the left electrode can be determined. If this concentration is less than at the right, then Ecell will approach 0 and the right electrode will be the cathode.

Jasmine Kim 1L
Posts: 71
Joined: Fri Aug 02, 2019 12:16 am

### Re: Concentration Cells

While galvanic cells have different ions reacting on the cathode and anode, concentration cells have the same species on either side, but the concentrations are different. That's why it's called a concentration cell.
The standard cell potential of a concentration cell is 0 because the reactions are exactly the same on either side, just reversed. This means that they have the same standard potential values. Using the equation $E^{\circ}_{cell}=E^{\circ}_{cathode}-E^{\circ}_{anode}$, the 2 values cancel out and Ecell is 0.

Sydney Myers 4I
Posts: 100
Joined: Fri Aug 09, 2019 12:17 am

### Re: Concentration Cells

The only reason that electrons flow is because of a difference in the concentration of the cells. They have the same species, which makes them generally have a lower E value than regular galvanic cells.

Return to “Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)”

### Who is online

Users browsing this forum: No registered users and 0 guests