c14 JWBS043-Rogers September 13, 2010 11:27 Printer Name: Yet to Come

14

ELECTROCHEMICAL CELLS

Advances in electrochemistry came at least a generation earlier than corresponding

advances in rigorous thermochemical theory. Even prior to Faraday’s numerous dis-

coveries, Alessandro Volta’s experiments on static electricity and electrical current

took place largely in the eighteenth century and culminated in the first true battery of

series voltaic cells. The battery was called a voltaic pile because cells were piled on

top of one another. Volta’s work excited great popular interest, especially when he

showed that Luigi Galvani’s use of a voltaic pile to activate nervous response in the

dissected leg of a dead frog depended on the electrical potential of the pile and was

not a property of the frog’s leg. Activation of a dead animal raised the question of

whether science might someday actually produce life.^1 News of Volta’s experiments

became something of a fad of the day. Mary Shelley’s popular creationFrankenstein

was presumably electrochemically activated.

14.1 THE DANIELL CELL

If you put a zinc rod into a solution of zinc sulfate ZnSO 4 , there will be a difference

in chemical potential between the Zn(s) in the metal rod and the Zn^2 +(aq) ion in the

aqueoussolution. A reaction takes place, causing a minute amount of Zn to dissolve

and go from the rod into the solution, leaving two electrons behind or, depending on

(^1) See Gibson, D. G. et al. 2010.Science, 329 , 52–56 for a claim that sciencehasproduced life.
Concise Physical Chemistry,by Donald W. Rogers
Copyright©C2011 John Wiley & Sons, Inc.
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