Physical and Chemical Changes

Physical Changes A change that alters the form or appearance, but does not make the material into a new substance. The properties change, but the particles are still the same. Examples Tearing paper Phase changes Crushing a can

Chemical Changes A change in matter that produces a substance with new properties. Both the physical and chemical properties of the substance will be changed.

Common Chemical Changes Burning/Combustion Rusting Tarnishing Digestion Photosynthesis

Chemical or Physical Change? A piece of metal is bent A bracelet turns green A plant makes its own food An apple rots Hair is cut

Chemical Reactions A process in which a substance undergoes a chemical change. If a chemical reaction happens, a chemical change has occurred.

Types of Chemical Reactions Exothermic Reaction: Heat EXITS It feels warm Temperature increases Examples: burning wood, “hot hands”

Types of Chemical Reactions Endothermic Reaction: Heat ENTERS Feels cold Temperature decreases Example: cold pack

Law of Conservation of Matter Atoms can rearrange during a chemical reaction but the amount that you start with is the amount that you end with. “Nothing is created nor destroyed”