Chemistry is a natural science that studies the nature, composition, structure, changes, uses, preparation methods and changing laws of substances.
Chemistry is closely related to industry, agriculture, daily life, medicine and materials. For example, the burning of coal, oil and natural gas will produce carbon dioxide and other substances. The object of chemical research involves the relationship between substances, or the relationship between substances and energy. Traditional chemistry often talks about the contact and change of two substances, that is, chemical reaction, or the process of one substance becoming another.
These changes sometimes require electromagnetic waves, which are responsible for stimulating chemical reactions. But sometimes chemistry is not necessarily about the reaction between substances. Spectroscopy studies the relationship between matter and light, which does not involve chemical reactions.