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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.
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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.