a. Write the half-cell reactions. At the negative plate (1.17 V):
"\\text{Ag}_2\\text{O} +2\\text{H}^++2\\text{e}^+\\rightarrow2\\text{Ag}+ \\text{H}_2\\text{O}."
In the electrolyte (-0.83 V):
"2\\text{H}_2\\text{O}\\rightarrow2\\text{H}^++2\\text{OH}^-."
At the positive plate (1.22 V):
"\\text{Zn}+2\\text{OH}^-\\rightarrow\\text{Zn(OH)}_2+2\\text{e}^-."
Write the overall reaction:
"\\text{Zn}+\\text{H}_2\\text{O}+\\text{Ag}_2\\text{O}\\rightarrow \\text{Zn(OH)}_2+2\\text{Ag}."b. Calculate the standard cell potential of this cell:
"E=E_1+E_2+E_3=1.17-0.83+1.22=1.56\\text{ V}."
c. The gravimetric capacity density for Zinc is 0.82 Ah/g. Therefore, the maximum possible energy density of this cell is:
"\\omega=1.7\\cdot0.82=1.394\\text{ kWh\/kg}."
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