Changes in matter

Physical Change Alters neither the nature nor the characteristic properties of matter. The atoms and molecules of the substance do not change

Chemical change Alters the nature and characteristic properties of matter. The bonds between atoms are rearranged, and new molecules are formed.

Chemical vs. Physical change Chemical change  can’t go back to original form Physical change  can go back to original form

Nuclear transformation The particle making up an atomic nucleus are rearranged and new elements are formed.

Chemical changes How to tell a chemical change has occurred:  release of a gas  emission or absorption of heat  emission of light  change in colour  formation of a precipitate

Types of chemical change Synthesis Decomposition Precipitation Acid – Base neutralization Oxidation Cellular respiration Photosynthesis

Oxidation A chemical change involving oxygen or a substance with properties similar to those of oxygen Ex. rusting

Combustion Combustion is a form of oxidation that releases a large amount of energy. Ex. Burning fuel

In class work P. 132-3 # 1, 2,,13, 18, 19, 20, 22, 23 State whether the following are physical or chemical changes: a) Log burning b) tree decomposing c) lake freezing d) crushing a block of ice e) melting a gold bar f) toasting bread