Concentration

[ursulavictorino1K]

How can you find the concentration of the anode or cathode given the concentration of the other? There was a question on the quiz which I did not understand how to solve that had this set up.

[Sidharth D 1E]

Are you referring to what to do given a concentration cell situation or in a galvanic cell?

[Ashley Nguyen 2L]

If you are referring to a galvanic cell, you would use the Nernst Equation, which is Ecell = Enot - RT/nF lnQ, where Q = [products]/[reactants]. If you are given all other variables, you can solve for the concentration of the anode or cathode.

[Paul Hage 2G]

If you are referring to a concentration cell, you would use the equation Ecell = Enaught - RT/nF lnQ. For a concentration cell, it is important to know that Enaught is 0. Therefore all you need to solve for a concentration of either the anode/cathode would be an Ecell value, the temperature, the constants in the equation, and the concentration of the other side of the cell. When you set up the Q expression within the Nernst equation, you can solve for the unknown value using the other values that are known.

[Long Luong 2H]

Another helpful tip to know is that the cathode is usually of higher concentration and is considered a reactant. Similarly, the anode is of lower concentration is the product for Q.

[Jacob Motawakel]

you use the nernst equation and make Q = [anode]/[cathode]

[Nawal Dandachi 1G]

You would use Ecell = Ecell o - RT/nF lnQ where Q would equal to [products]/[reactants] and in that situation, it was [anode]/[cathode]

[Rohit Ghosh 4F]

They way you'd figure out if the anode or the cathode was in the numerator is by looking at the overall reaction. Products are always in the numerator and reactants are in the denominator.

[ABombino_2J]

You need to use the NERNST equation album make sure you set up Q as [anode]/[cathode].

[Nathan Nakaguchi 1G]

E and T were given and R is a constant (8.314 J/Kmol). E^0= 0 since this is a concentration cell. The question also provided that the cathode reaction had some concentration which for concentration cells is the [R] in Q. Considering that the redox reaction was Cu2+(aq) to Cu(s) the value of n should be 2 since the redox reaction should be Cu2+ + 2e- -> Cu(s). From here you have one equation and one unknown [P] which corresponds to the anode concentration, solve for that and you're done!