Chemistry Final Study Guide Chapter 1- Matter and Change Chemistry - is the study of the composition, structure, and properties of matter, the processes that matter undergoes, and the energy changes that accompany these processes. Chemical ? any substance with a definite composition. Mass ? measure of the amount of matter Matter ? anything that takes up space Atom ? the smallest unit of an element that maintains the chemical identity of that element Element - pure substance that cannot be broken down into simpler, substances and is made of one type of atom Compound ? a substance that can be broken down into simple stable substances. Each compound is made from the atoms of two or more elements that are chemically bonded