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Published byJoshua Matthews Modified over 8 years ago
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PHYSCIAL CHANGES When a substance changes form or state. (although the substance remains the same) Example: The chocolate dip ice cream cone. LIQUID (chocolate) SOLID (chocolate) TRY TO COME UP WITH OTHER EXAMPLES OF PHYSICAL CHANGE
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CHANGES OF STATE SOLID LIQUID GAS melting freezing (solidification) vaporization (evaporation) condensation sublimation Can you think of examples???
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CHEMICAL PROPERTIES Describes the ability of a substance to react with another substance to form one or more new substances (chemical reactions) 1.combustibility - the ability of a substance to burn in air ex. hairspray, propane (very combustible) 2. reaction with water/ oxygen / acids ex. gold does not react quickly with oxygen silver oxidizes (tarnishes) with oxygen
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CHEMICAL CHANGES When a substance is changed into one or more different substances that have different properties. Example: combustion – burning propane (C 3 H 8 ) O2O2 +C3H8C3H8 CO 2 +H2OH2O light/ heat + REACTANTSPRODUCTS CHEMICAL EQUATION
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Chemical reactions which r elease energy (i.e. feel hotter) are called: EXOTHERMIC REACTIONS Chemical reactions which a bsorb energy (i.e. feel colder) are called: ENDOTHERMIC REACTIONS
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IDENTIFYING A CHEMICAL CHANGE Colour change ( note: does not always mean a chemical change has occurred ) 2. Heat or light is produced
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3. Bubbles/gas are formed. A solid material ( precipitate ) forms in a liquid. 5. The change is difficult to reverse.
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BURNING CANDLE Physical or chemical change? Burning wick (chemical) Melting wax (physical) dripping wax (physical)
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