ELECTROCHEMISTRY
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1. The electrochemical cells
2. Electrodes
3. Electrochemical power sources
4. Electrolysis
Oxidation number refers to the charge that atom would have if it was composed of ions. Oxidation
state or oxidation number describes the degree of oxidation of an atom in a chemical compound
Electrodes, conductors which electricity enter or leave. An electrode contains at least two conductive
phases, one phase is electron conductor, another is ion conductor.
Classification of the electrodes:
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First kind electrodes, an element and its oxidized/reduced form is involved. For
example, metal electrodes and gas electrodes
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Second kind electrodes: a metal contacts to its weakly soluble salt and it is
immersed in the solution of the anion of the salt
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Redox electrodes: both the oxidized and reduced forms are in the same phase
Electrochemical cell contains at least two electrodes which are connected to each other.
Cell diagram is the most compact notation of an electrochemical cell (or electrode)
Galvanic cell (voltaic cell): one kind of an electrochemical cell in which chemical reactions produce
electric work
Electrolytic cell: another kind of electrochemical cell in which electric work cause chemical changes
Electrolysis: electric works cause chemical changes
Salt bridge: tube filled with inert electrolyte solution
Ecell = Ecathode – Eanode
Standard hydrogen electrode (SHE) is a half-cell based on hydrogen ion production, assigned a
potential of exactly 0 V under standard state conditions, used as the universal reference for
measuring electrode potential
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EMF measurement using extrapolation technique
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EMF measurement using the compensation technique