In chemistry, catalysis is the addition of a substance that is not consumed during the reaction to change the rate of a chemical reaction, usually an acceleration. The velocities at which chemical reactions occur are determined by a variety of factors, including the chemical composition of the reacting species and the external conditions to which they are exposed. Catalysis, or the acceleration of chemical reactions by chemicals that are not consumed in the events themselves—substances known as catalysts—is a particular phenomenon connected with the speeds of chemical reactions that is of enormous theoretical and practical relevance.
Chemical Science is a discipline of natural science concerned with the composition of substances, as well as their properties and reactions. The scientific study of matter's properties and behaviour is known as chemistry. It is a natural science that studies the elements that make up matter, as well as the compounds made up of atoms, molecules, and ions: their composition, structure, qualities, and behaviour, as well as the changes that occur when they mix with other things.