Physical and Chemical Properties and Changes

Physical Property A physical property is any characteristic of a material that can be observed WITHOUT changing the identity of the material itself Characteristics that can be observed or measured Color Length Shape Temperature Density Melting point Boiling point -thermal conductivity Electrical conductivity

Physical change A physical change is any change in the size, the shape, or the state of the matter in which the identity of the substance is unchanged Physical changes: Dissolving Mixing Changes in state Freezing, boiling, condensation, vaporization, sublimation, deposition

Chemical properties A chemical property is the ability or inability of a substance to combine with or change into one or more new substances Properties like: Flammability: ability to burn Paper can burn Hydrogen burns in air Rust: reactivity with oxygen/water/others Iron will rust Aluminum reacts with acid Silver tarnishes from sulfur in foods Inability to react or burn Helium gas does not burn, carbon dioxide is nonflammable Gold and platinum will not corrode (rust) Copper and silver do not react with water

Chemical and Physical changes When a substances changes, its properties change. Ice melts Iron rusts Growing taller Digested food becomes part of your body With some substances, chemical properties can also change Food you eat is changed due to disgestion process Iron rusting forms a new compound, iron oxide

Chemical changes A chemical change is the change of one or more substances into other substances In chemical changes, the atoms rearrange and form one or more new substances Not easily reversed Paper burns, ashes, can’t go back to paper Food you eat, digest, poop, can’t go back to food Physical changes on the other hand can be reversed