Rates of
Reaction Catalysts and
Energy Search Questions 
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Catalysts - What is a Catalyst?
A catalyst is a substance that will change the rate of a
reaction.
A catalyst is often used to make a reaction go faster.
The catalyst itself does not take part in the
reaction as a reactant.
It is not changed by the reaction, it is not
used up during the reaction.
It is still there in the same form when the reaction is complete.
A catalyst is usually a transition metal, a transition metal oxide
(see uses of transition metals) or
an enzyme in
living cells.
An exception is aluminium oxide, used in the cracking of
hydrocarbons.
A substance which works well as a catalyst for one
reaction
might not work well as a catalyst for
a different reaction.
How does a catalyst work?
A catalyst works by
providing a convenient surface for the
reaction to occur.
The reacting particles gather on the catalyst surface
and
1) collide
more frequently with each other
2) more of the collisions result in a reaction between particles
because the catalyst can lower the activation energy
for the reaction.
A catalyst is often used as a powder,
so that it has a bigger surface area per
gram.
Rates of
Reaction Catalysts and
Energy Search Questions
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