- Slides: 6
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.