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Introduction to Chemical Reactions: physical and chemical changes. CLASS NOTES. Elements and Compounds. An element is a substance that contains only ____ kind of atom Compound is a pure substance that is made of up ______ or more elements Elements and compounds are created through bonding
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Introduction to Chemical Reactions: physical and chemical changes CLASS NOTES
Elements and Compounds • An element is a substance that contains only ____ kind of atom • Compound is a pure substance that is made of up ______ or more elements • Elements and compounds are created through bonding • What are the two different types of bonding?
Chemical reactions produce changes… • TWO types of changes: physical and chemical • Physical change: • Change in state: solid, liquid or gas • May change in colour • Chemical change: forms a new substance • Heat may be produced For example: newspaper physical change: can make a ball of newspaper chemical change: sun’s energy can turn the paper yellow is you leave it in the sun
Physical or Chemical Change? • Butter melting • Digestion of foods in your body • Bubbles of gas escaping from a soda • Rust on a car • Lake freezing (turning to ice from water)