Pure substances have fixed chemical composition throughout. Pure substances can exist in solid, liquid, and gas phases. Molecular bonds are strongest in solids, weakest in gases
Systems are classified as homogeneous or heterogeneous based on physical characteristics. A phase is a distinct portion of a system maintaining same properties. Three main phases exist: solid, liquid, and gas
Matter exists in three states: solids, liquids, and gases. Particle arrangement determines state: solids have strong forces, liquids moderate, gases negligible. New states: plasma (electrons and ions) and Bose-Einstein condensate (atoms in single quantum state)