C2(ii) - Rates of Reaction 5.
- Created by: Alice Ugg-Boots
- Created on: 21-05-11 12:14
Catalysts.
Many reactions can be speeded up by adding a catalyst.
A catalyst is a substance which changes the speed of a reaction, without being changed or used up in the reaction.
1) Catalysts Lower the Activation Energy.
a) The activation energy is the minimum amount of energy needed for a reaction to happen.
b) It's a bit like having to climb up one side of a hill before you can fall down the other side.
c) Catalysts lower the activation energy of the reaction, making it easier for it to happen.
d) This means a lower temperature can be used.
2) Solid Catalysts Work Best When They Have a Big Surface Area.
a) Catalysts are usually used as a powder or pellets or a fine gauze.
b) This gives them a very large surface area to enable the reacting particles to stick to giving more chance for a collision.
c) Transition Metals are common catalysts in many industrial reactions, e.g. nickel is used for…
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