1. CATALYSTS

2. A catalyst is a substance which speeds up the rate of a reaction without being chemically changed. A catalyst lowers the temperature at which a reaction occurs. This means that catalysts can be re-used for other experiments. Catalysts normally have a large surface area.

3. Some car exhausts have CATALYTIC CONVERTERS. Catalytic converters change harmful chemicals in exhaust fumes into less harmful chemicals. Many catalytic converters are made from transition metals such as Platinum, but these can be very expensive. Although catalysts can be re-used and remain unchanged in a reaction, they may eventually become unusable. We say that the catalyst has become ‘poisoned’.

4. Industries use catalysts because they:- Allow the reaction to occur at a lower temperature. Save money for the company. Reduce pollution levels.