Physical and Chemical Properties Characteristics used to identify or describe all matter.

Words to know Electromagnetic force – the force that holds the nucleus of an atom together. Quantum Mechanics – The study of atoms and their composition.

Characteristic Properties The properties of a substance used to identify or describe matter in terms of its characteristics. When we say that water is “wet” or that silver is “shiny” we are describing these items in terms of their properties.

Physical Properties Readily Observable – Color – Size – Odor – Boiling Point or Freezing Point or Melting Point – Density – Magnetism

Physical Properties - can not change the chemical nature of matter. Every substance has a set of characteristic properties that do not change no matter its size or shape.

Physical Changes (Reactions) A Physical Change does not create a new substance. Examples Melting, freezing, vaporization, condensation. Crushing a can, wading up a piece of paper, or breaking a bottle.

Chemical Properties Only observable during a chemical reaction – Heat of combustion – Reactivity with water – PH (acidity or baseness) – Electromotive force (potential electrical current produced – i.e. a battery)

Chemical Properties can change the chemical nature of matter. When substances react chemically, one or more new substances are created. Chemical changes are typically irreversible.

Chemical Changes (Reactions) Chemical Changes take place on a molecular level. Examples Combustion (burning) and cooking an egg. Rusting of an iron pan Mixing Hydrochloric Acid and Sodium Hydroxide to make salt and water.

Molecular Rearrangement During a chemical reaction, the atoms (that are linked together) rearrange to make new molecules. The new substance is still made of the same kinds of atoms, they are simply linked together differently. If the atoms do not rearrange, a chemical reaction did not occur.

Baking Soda & Vinegar chemical reaction NaHCO 3 + HC 2 H 3 O 2 → NaC 2 H 3 O 2 + H 2 O + CO 2 In this reaction, a solid and a liquid create completely different compounds after the reaction is finished. Notice that two of the compounds created are simple water and carbon dioxide!