That's a safe but perhaps overly terse definition, considering that matter is anything with mass that occupies space. Chemistry is a systematic study . Chemists have devised several good methods for solving problems and making observations. Chemists use well-defined techniques like spectroscopy and chromatography to study new or unknown substances. Chemistry is the study of the composition and properties of matter .
Chemistry is the study of the reactivity of substances .
One material can be changed into another by a chemical reaction. A complex substance can by made from simpler ones. Chemical compounds can break down into simpler substances. Fuels burn, food cooks, leaves turn in the fall, cells grow, medicines cure. Chemistry is concerned with the essential processes that make these changes happen.