17.5 Batteries and Fuel Cells

Consider a battery with the overall reaction: $\text{Cu} \left(s\right) + 2 \text{Ag}^{+} \left(a q\right) \rightarrow \text{2Ag} \left(s\right) + \text{Cu}^{2+} \left(a q\right) .$

(a) What is the reaction at the anode and cathode?

(b) A battery is “dead” when its cell potential is zero. What is the value of Q when this battery is dead?

(c) If a particular dead battery was found to have [Cu²⁺] = 0.11 M, what was the concentration of silver ion?

Why do batteries go dead, but fuel cells do not?

Automobile batteries are often rated with regard to “cold-cranking amps,” a measure of the ability of the battery to perform in low-temperature weather. Suggest a reason to explain why a battery’s ability to deliver current is diminished at low temperatures. (Hint: Consider the kinetics of chemical reactions.)