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Redox
OILRIG!
A reaction where a chemical is Oxidised and another is Reduced.
How to construct one:
Step one: Identify reduction and oxidisation half equations
E.g.
FeFe(3+)+3e(-)
Cu(2+)+2e(-)Cu
Step two: Balance the equations
E.g.
2Fe2Fe(3+)+6e(-)
3Cu(2+)+6e(-)3Cu
Step three: Add the two half equations together and cancel the electrons
E.g. 3Cu(2+)+2Fe2Fe(3+)+3Cu…read more

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Half cells
A half cell comprises of an element in two oxidisation states, the most simple half
cell is a metal strip in an aqueous solution of its ions.
Equilibrium exist ant the surface of the strip e.g.
2e(-)+Cu(2+)(aq)Cu(s)
The electrode potential of a half cell is its tendency to lose or gain electrons…read more

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Electrochemical cells
One half of the cell releases electrons
The other half of the cell gains electrons. E.g.
Zn(2+)(aq)+2e(-)Zn (s)
Cu(2+)(aq)+2e(-)Cu(s)
The Zn/Zn(2+) releases e(-) easier than the other.
Therefore e(-) move from Zn to Cu…read more

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Determining electrode potentials
To do this a reference cell is used, it's potential is zero.
An example is the standard hydrogen electrode (SHE)
Cell potentials is measured.
The largest number-smallest.
E.g.
Ag/Ag(2+) half cell= +0.80v
Cu/Cu(2+) half cell=+0.34v
So 0.80-0.43=0.46
So this would be the cell potential of this cell.…read more

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Key terms
Cell potential: The e.m.f. between two half cells making up a cell
Standard cell potential: Difference between the standard electrode potential of the
half cells
Cell Reaction: Overall reaction taking place in a cell. Sum of the reduction and
oxidisation half reaction taking place in each half cell.…read more

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