Inorganic and Applied Chemistry

Download free books at BookBooN.com

Inorganic and Applied Chemistry

6.2.2 Cell potentials

A galvanic cell consists, as we have seen, in principle of an oxidation component in a container that draws

electrons through a wire from a reduction component in another solution. The driving force causing the

transfer is called the cell potential or sometimes the electromotoric force (in short EMK). The unit for cell

potentials is volt (in short: V) defined as joules of work coulomb charge transferred. The electromotoric

force is defined as:

arg ( )

( )

ch e C

work J

EMK cellpotential (^) (6- 1)
In order for a cell reaction to take place spontaneously it is necessary that the cell potential is positive.
6.3 Standard reduction potentials
The reaction in a galvanic cell is always a redox reaction that ay be divided into two half-cell reaction is a
similar fashion as we have seen it earlier. As well as there is a cell potential for the whole cell there is also a
half-cell potential associated with the half-cell reaction. The ell potential for the entire cell is thereby the sum
of the two half cell-reactions. This we will look further into in the following example.
Electrochemistry
http://www.job.oticon.dk