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Oxidation and Reduction.
What is Oxidation and What is Reduction?
Oxidation
means losing
electrons
and
reduction means gaining electrons.
In the reaction between iron and copper(II) sulfate
Fe(s) + Cu2+(aq) Fe2+(aq) + Cu(s)
Iron metal
(Fe(s)) loses 2 electrons to
form iron ions
(Fe2+(aq))
Fe(s) -
2e-(aq)
Fe2+(aq)
This is
called oxidation. Iron is said to be oxidised.
Copper ions
(Cu2+(aq)) gain 2 electrons to
form copper
metal (Cu(s))
Cu2+(aq)
+ 2e-(aq)
Cu(s)
This is called reduction. Copper is
said to be reduced.
To help you to remember that oxidation
means losing electrons
and reduction means gaining electrons,
remember O I L R I G
(Oxidation Is Loss, Reduction Is
Gain - of electrons).
Oxidation and reduction always
occur together.
They are called redox reactions
(pronounced "reed - ox" for reduction /
oxidation).
Oxidation may also be defined as gaining oxygen
and reduction defined as losing oxygen.
For example, when copper(II) oxide is heated with carbon
copper(II)
oxide + carbon copper + carbon
dioxide.
2CuO(s) +
C(s) 2Cu(s) + CO2(g)
Carbon is
oxidised by gaining oxygen to
form carbon dioxide.
Copper (in CuO) is reduced by losing
oxygen to form
copper
metal.
Note that copper has changed from Cu2+ (in CuO) to Cu(s)
and so has gained electrons.
Cu2+(aq)
+ 2e-(aq)
Cu(s)
Links The Reactivity Series Revision Questions
gcsescience.com The Periodic Table Index Reactivity Series Quiz gcsescience.com
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