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  A catalyst (Greek, ‘looser’) is a substance which changes the speed of a chemical reaction without being changed or consumed in the reaction. Many substances act as catalysts, for example platinum silver and oxides such as vanadium pentoxide.

The application of catalysts in industry is enormous. One of the first uses of a catalyst was the use of iron ore magnetite to combine hydrogen and nitrogen to produce ammonia on an economical scale. The addition of this catalyst meant that hydrogen and nitrogen could now be combined using less energy than before, which in turn led to the process of an economic product.

Since the catalyst does not take part in the chemical reaction, it is only the surface area that does the work in speeding up the reaction. It is therefore important to expose as much of the surface area as possible, especially with precious metals such as platinum. This surface area can become ‘poisoned’ and therefore makes the catalyst less effective with use.

Catalysts are found in living organisms and are known as enzymes, which break down organic material. Enzymes are used to digest food, make food and beverages and are also used in the pharmaceutical industry. AA



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