AP Chemistry / Unit 9: Thermodynamics and Electrochemistry
9.9 Cell Potential and Free Energy
Notes
$$E^\circ_{cell}=E^\circ_{cathode}-E^\circ_{anode},\qquad \Delta G^\circ=-nFE^\circ$$
- Positive $E^\circ$ means $\Delta G^\circ<0$ (favorable).
Practice
$E^\circ_{cathode}=+0.80$ V, $E^\circ_{anode}=-0.76$ V. $E^\circ_{cell}$:
$0.80-(-0.76)$.
A positive cell potential means:
$\Delta G=-nFE$.
In $\Delta G^\circ=-nFE^\circ$, $n$ is:
From the balanced half-reactions.
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