Catalysts are substances that speed up chemical reactions without being used or chemically changed in the process. This means that the mass of the catalyst remains the same before and after the reaction.
Catalysts are specific in the sense that they only work with certain types of chemical reactions. A catalyst will only work if it can interact with the reactants in a way that speeds up the reaction. This is why different catalysts are used for different chemical reactions.
You only need a small amount of a catalyst to speed up a chemical reaction. Using more of the catalyst than necessary won’t significantly increase the reaction rate. Using more of the catalyst than needed will not make the reaction happen much faster
Enzymes are biological catalysts that speed up chemical reactions in living organisms. For example, amylase catalyses the breakdown of starches (complex carbohydrates) into simpler sugars such as glucose.
The exhaust systems of cars contain catalytic converters, which reduce the release of toxic pollutants from the exhaust pipe. They do this by converting harmful substances into less harmful substances.
Three pollutants that catalytic converters target are nitrogen oxide, carbon monoxide and hydrocarbons.