$delta_G$ = -nFE connects electrochemistry to thermodynamics. delta_G_{standard} = -$nFE_{standard}$. Since $delta_G$ = $delta_H$ - T*$delta_S$, and $\frac{partial E}{partial T}$_P = $\frac{delta_S}{nF}$, we get: $delta_S$ = nF$\frac{dE}{dT}$_P (temperature coefficient of EMF). $delta_H$ = $delta_G$ + T*$delta_S$ = -nFE + nFT$\frac{dE}{dT}$. If dE/dT > 0, the reaction absorbs heat from surroundings (endothermic contribution). If dE/dT = 0, $delta_G$ = $delta_H$ (no entropy change). The relationship delta_G_{standard} = -RT*ln(K) = -$nFE_{standard}$ connects all three: equilibrium, thermodynamics, and electrochemistry.