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Science

Rates of reaction

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Catalysts

Effect of catalysts

A catalystcatalyst: A catalyst changes the rate of a chemical reaction without being changed by the reaction itself. is a substance that can increase the rate of a reaction. The catalyst itself remains unchanged at the end of the reaction it catalyses. Only a very small amount of catalyst is needed to increase the rate of reaction between large amounts of reactants.

Different catalysts catalyse different reactions. The table summarises some common catalysts used in industry and the reactions they catalyse:

Some common catalysts used in industry and the reactions they catalyse

CatalystReaction catalysed
IronMaking ammonia from nitrogen and hydrogen
PlatinumMaking ammonia from nitrogen and hydrogen
Vanadium(V) oxideMaking sulfuric acid

Catalytic converters

Modern cars have a catalytic converter to help reduce the production of toxic gases. Catalytic converters use a platinum and rhodium catalyst with a high surface area. This increases the rate of reaction of carbon monoxide and unburnt fuel from exhaust gases with oxygen from the air. The product from this is carbon dioxide and water, which is less harmful to the environment. The catalysts are designed to work best at the high temperatures found in the engine.

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