CHEMISTRY COMMUNITY

When finding Q in the nernst equation, is it always [cathode]/[anode] or is it [anode]/[cathode] ?

It can be determined by the overall cell reaction, with the concentrations plugged in for Q (products over reactants)

I believe its [anode]/[cathode]

I believe that it is [anode]/[cathode].

Q is [Products]/[Reactants] so it depends on the chemical equation.

Q should be anode/cathode.

I was told that it is anode/cathode when using this equation.

anode/cathode

anode looses mass, cathode gains mass

It should be Anode over Cathode.

Q= [anode]/[cathode]

Q is a reaction quotient, which means that for most redox reactions, as long as you have the balanced equation, it should look identical to the equilibrium expression (with appropriate exponents to match the coefficients in the balanced equation). The equilibrium expression always puts products in the numerator and reactants in the denominator.

For example, looking at the generic redox equation A+(aq) + B (s) --> A(s) + B+(aq), the only concentration on the products' side is [B+] and the only concentration on the reactants' side is [A+]. Note that in this case, A+ is the species being reduced, meaning it is being consumed like a reactant at the cathode. Similarly, B(s) is the species being oxidized, meaning B+ is being produced like a product at the anode. Thus, since the coefficients are all 1 in this case, Q = [B+]/[A+] = [Anode ion]/[Cathode ion].

Q = [products]/[reactants] so it would be [anode]/[cathode]

I think its easier to think products/reactants.