01Nernst intuition
As a battery runs, Q rises and E falls; at equilibrium E = 0 (a dead battery). E = E° − (RT/nF) ln Q.
Increase reactant concentration → Q smaller → E larger. AP mostly asks qualitatively.
02Notebook box
Q < 1 → E > E°. Q > 1 → E < E°.
Worked example: Zn/Cu cell with [Cu²⁺] raised → E above 1.10 V.