Concentrations

[Giselle Littleton 1F]

How is the voltage of a galvanic cell affected by anode/cathode concentration?

[Shrayes Raman]

Related by E=E* - RT/fnln(conc cathode/conc anode) although depends on problem.

[Aarushi Solanki 4F]

The voltage of the cell is related to the concentrations as seen by the equation E = E* - (RT/Fn)lnQ. Q is concentration-dependent, so E is concentration-dependent.

[David Chibukhchian 2G]

I understand the equation E = E* - (RT/Fn)lnQ when it comes to the relation between concentration and voltage; however, I am a bit confused as to what the term E* specifically means. How does it differ from the E at the left-hand side of the equation? If someone could clear that up for me that'd be really helpful!

[Vanshika Bhushan 1A]

By changing the concentration of one solution, you increase the number of cations and anions in the cell. This will increase the voltage potential of the cell because you are putting the system further out of equilibrium.

[DMaya_2G]

The voltage of the cell is connected to the concentrations, which is seen by the equation E = E* - (RT/Fn)lnQ. Both Q and E are concentration-dependent.

[Neel Bonthala 2G]

I understand the equation E = E* - (RT/Fn)lnQ when it comes to the relation between concentration and voltage; however, I am a bit confused as to what the term E* specifically means. How does it differ from the E at the left-hand side of the equation? If someone could clear that up for me that'd be really helpful!

Hey! So E* is essentially the cell potential at standard conditions (1 mole of solution at anode and cathode, 25 degrees celsius) and is measured with respect to to the standard hydrogen electrode. Think of it kind of as G*, in which it was the G value for a reaction at standard conditions. E does not use standard reduction potentials, and occurs at different conditions (varying concentrations, etc.). I hope that clears it up a bit!

[Kandyce Lance 3E]

The voltage of the cell is connected to the concentrations, which is seen by the equation E = E* - (RT/Fn)lnQ. Both Q and E are concentration-dependent.

What do we need to do when we don't know E*?

[Mackenzie Stockton 2H]

Because E = E* - (RT/Fn)lnQ, the voltage of a cell depends on concentration