Chemical and Physical Changes

Physical Changes A change in the size, shape, state, or form of matter. No new substance is made. Ex Crumpling paper Dissolving Ice melting Cutting something in half Blowing up a balloon

Chemical Changes A change in matter where one or more substances change into new substances with different chemical and physical properties. Ex: Fire After a log is set on fire, it is not a log anymore, it is ash and gas.

How to Spot a Chemical Change A NEW gas is made When a new gas is formed, it is a new substance that has been made. If a substance changes into its gas form, that is a physical change. A precipitate forms When two or more substances are combined and a new solid forms. Color change Color changes indicate chemical change.

Energy and Chemical Change Chemical changes require energy changes. Energy is taken in Baking food Baking soda and vinegar Energy is released Fireworks bombs

Reversing a Change Most chemical changes cannot be reversed Fireworks cannot change back You can’t remake an Alka-Seltzer tablet Some physical changes can be reversed You can flatten out a piece of paper You cannot un-grate a carrot You can separate salt from water it was dissolved in.