Please make it simple because I need it for school and please give to examples for the second part Thanx :D
A catalyst is a substance that speeds up the rate of a chemical reaction with itself being chemically unchanged at the end of the reaction. They are useful as they help to lower the minimum amount of energy needed ( also known as activation energy) to start the reaction. Hence, by lowering the activation energy of the reaction, they help to speed up the rate of reaction. For example, in the Haber process for the manufacture of ammonia, the catalyst iron is added to speed up the rate of reaction between hydrogen gas and nitrogen gas. Otherwise, the reaction would have proceeded much more slowly. Another example is the catalyst nickel used in the manufacture of margarine and vanadium (V) oxide for manufacturing sulfuric acid. As catalyst remain chemically unchanged after a reaction, they can be reused again and hence, they are required in minute amounts. An example is the washing powder used in washing clothes, they help to remove food stains by digesting the proteins in food. They can be reused after each reaction and hence, you do not need to add in the whole packet of washing powder but only a few spoonful.
