1).
Heart pacemakers are often powered by lithium-silver chromate “button”
batteries.The overall cell reaction is:

2Li(s) +Ag₂CrO₄(s) ——–>
Li₂CrO₄(s) + 2Ag(s)

(a)
Lithium
metal is the reactant at one of the electrodes of the battery.Is it the anode or the cathode?

(b)
Choose
the two half-reactions from a table of standard reduction potentials that most
closely approximate the reaction that occur within the battery.What is the standard voltage generated by a
cell operating with these half-reactions?

(c)
The
actual value is about +3.5 V for this pacemaker cell.How does that compare to what you’ve shown me
in (b)?

(d)
Calculate
the voltage at body temperature,

3).Hydrogen
gas burns cleanly by the flowing simple reaction:

H₂(g)+O₂(g)———->2H₂O(l)

(a)
Use
data from a table of thermochemical measurements to determine the values forDH°
andDS° for the reaction.
Calculate DG° from those values at 25°C.

(b)
Show
the half-cell reactions in a hydrogen fuel
cell, and calculate the standard voltage at 25°C

(c)
Is
it more efficient to burn hydrogen to generate heat to drive a turbine to
produce electricity, or simply to produce electricity directly in a fuel cell
reaction?Speculate on large versus
small scale power generation, and the fact that hydrogen can be piped in to
homes and businesses as natural gas is now.