Physical & Chemical Changes

Physical & Chemical Changes

	Physical Change	Chemical Change
Definition	No new substance is produced Substance remains the same even with a change of state May require addition of energy Release of energy may occur	Final substance is substantially different than initial substance New substance is always produced Energy is usually released but may be required to get the change going
Properties	Outside may look different Inside remains the same Particles may be rearranged Forces of attraction between particles may be weaker or stronger	A new substance is produced The particles of the new substance do not resemble those of the old substance Internally, the substance produced is different than the old substances
Examples	Mixing sugar and water Ice melts into water Solid wax ==> Liquid wax	Vinegar and baking soda mix to form carbon dioxide Hydrochloric acid reacts with magnesium metal to form hydrogen gas

CHANGES OF STATES OF MATTER

When a state of matter gains or looses heat it undergoes a change.

A gain in heat is called an endothermic change. A loss in heat is called an exothermic change.

The table below summarizes the six changes of states that matter can undergo and tells you if heat is added or removed for the change to take place.

Change	From	To	Heat	Examples
Sublimation	solid	gas or vapour	added = endothermic	Moth crystals disappear when left in a closet for several days
Sublimation	gas or vapour	solid	removed = exothermic	frost forms on a car's windshield
Evaporation or vapourization	liquid	gas	added = endothermic	Rain dries up when the sun comes out
Melting or Liquefaction	solid	liquid	added = endothermic	An ice cube turns into water when left out of the freezer
Freezing or Solidification	liquid	solid	removed = exothermic	A bottle of water will turn into ice if left in the freezer
Condensation	gas or vapour	liquid	removed = exothermic	Drops of water form on the mirror when taking a hot shower