$word_{count}$: 200

The Nernst equation relates cell potential to concentration: E = $E_{standard}$ - $\frac{RT}{nF}$ln(Q). At 25 C: E = $E_{standard}$ - $\frac{0.0592}{n}$log(Q). Here n = electrons transferred in the balanced equation, Q = reaction quotient. Key applications: (1) Calculating $E_{cell}$ at non-standard concentrations. (2) Concentration cells ($E_{standard}$ = 0): E = $\frac{0.0592}{n}$log$\frac{C_high}{C_low}$. (3) Finding K from $E_{standard}$: at equilibrium E = 0, so $E_{standard}$ = $\frac{0.0592}{n}$log(K). (4) Thermodynamic link: $delta_G$ = -nFE connects free energy to cell potential. delta_G_{standard} = -$nFE_{standard}$ = -RTln(K) unifies electrochemistry, thermodynamics, and equilibrium. Temperature coefficient: $delta_S$ = nF$\frac{dE}{dT}$, $delta_H$ = -nFE + nFT$\frac{dE}{dT}$. Common traps: $E_{standard}$ is intensive (doesn't change when reaction is scaled), but $delta_G$ is extensive (scales with n). Always identify n from the balanced equation before applying Nernst.