Matter is anything that has mass and takes up space. It can be classified into different phases or states of matter - solid, liquid, or gas - based on the particle properties, proximity, energy, and volume or shape of the particles. The document distinguishes between physical and chemical properties and changes. A physical change does not produce a new substance, while a chemical change results in the formation of a new substance through a chemical reaction. Chemistry is the study of matter and its changes at the atomic and molecular level.