A, energy stored in chemical bonds of molecules, is correct because chemical energy is the potential energy in the molecule, for example the chemical energy in coal is converted to electrical energy through power plants. The energy was already stored in the coal, just in a different form.
The formula of work is Work (Joules)=Force (Newtons) · distance in the direction of the force (meters), therefore its just a matter of replacing factors.
Work done = 12 · 4.5= 54 joules
Answer: Thus the cell potential of an electrochemical cell is +0.28 V
Explanation:
The calculation of cell potential is done by :

Where both
are standard reduction potentials.
![E^0_{[Fe^{2+}/Fe]}= -0.41V](https://tex.z-dn.net/?f=E%5E0_%7B%5BFe%5E%7B2%2B%7D%2FFe%5D%7D%3D%20-0.41V)
![E^0_{[Pb^{2+}/Pb]}=-0.13V](https://tex.z-dn.net/?f=E%5E0_%7B%5BPb%5E%7B2%2B%7D%2FPb%5D%7D%3D-0.13V)
As Reduction takes place easily if the standard reduction potential is higher(positive) and oxidation takes place easily if the standard reduction potential is less(more negative). Thus iron acts as anode and lead acts as cathode.
![E^0=E^0_{[Pb^{2+}/Pb]}- E^0_{[Fe^{2+}/Fe]}](https://tex.z-dn.net/?f=E%5E0%3DE%5E0_%7B%5BPb%5E%7B2%2B%7D%2FPb%5D%7D-%20E%5E0_%7B%5BFe%5E%7B2%2B%7D%2FFe%5D%7D)

Thus the cell potential of an electrochemical cell is +0.28 V