Properties can be? Physical - can be observed without changing identity or composition of the substance Ex. Color, odor, Density, Melting Point, Boiling Point, Hardness Chemical - describe the way a substance may change or react to form other substances Ex. Flammability - the ability of a substance to burn in the presence of oxygen Intensive - do not depend on the amount of sample being examined Help to identify substances Ex. Temperature, melting point Extensive - Depend on the amount of sample Help to show quantity of a substance Ex. Mass, volume Physical and Chemical Changes Physical Change - substance changes its physical appearance, but not its composition Changes of state are physical changes Chemical Change - substance changes into a chemically different substance