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Physical and Chemical Changes Physical Change:  Changes affecting the form of a substance, but NOT its chemical composition  New properties can appear.

Properties of Matter Colour Odour Hardness Melting/Freezing Point Boiling Point Luster  How shiny a substance is Malleability  The ability of a substance to be beaten into thin sheets Conductivity  The ability of a substance to allow the flow of energy or electricity Mass Weight Volume Height Density  The mass of a substance divided by its volume

Physical and Chemical Changes Chemical Change:  Change in chemical composition  Always causes at least one new substance to be formed with new properties.

Indicators of Change Heat loss or gain New substance formed New properties formed New colour appears Colour disappears Starting material used up Gas bubbles formed Solid (precipitate) forms Light given off Change in state Change in texture

How are Chemical and Physical Changes Alike? Both are changes New properties Take time Involve matter New colour (appear or disappear) Changes in texture

CHEMICAL PHYSICAL New substance New molecular formula No new substance No new molecular formula How are Chemical and Physical Changes Different ?

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Physical vs Chemical Changes Answer Key PHYSICAL CHEMICAL PHYSICAL CHEMICAL PHYSICAL CHEMICAL

Physical vs Chemical Changes Answer Key PHYSICAL CHEMICAL PHYSICAL CHEMICAL PHYSICAL CHEMICAL PHYSICAL

Physical and Chemical Changes Answer Key SituationType of Change Explanation 1. A piece of dry ice (solid carbon dioxide) is dropped into hot water. Large amounts of white vapour bubble out of the water. PhysicalIt’s simply a change of state. Sublimation. 2. When George’s father makes wine from crab apples, bubbles form on the surface of the yeast and fruit mixture ChemicalYou cannot revert back to the original ingredients. 3. When margarine is left in a warm place for an extended period of time, it tastes sour. ChemicalIt is changing its chemical composition. Once something sours, you cannot get it back into its original form. 4. Jane’s father opens up a new deodorant product. The room quickly smells like fresh flowers. PhysicalThe molecules of air are not being changed, just a new substance sprayed to make a scent. 5. During a school volleyball game, Jennifer sprains her ankle. Her coach squeezes a bag at room temperature that quickly becomes very cold. ChemicalThere is a chemical reaction happening which allows for the sensation of cold. Once the reaction wears off you cannot go back to the original state.

Chemical and Physical Changes Demos  Burn sugar and salt – which is easier? Why?  Make kool-aid (water and sugar)  Burn a candle (releases CO2, heat)  Make pancakes  Alka-seltzer in water  Coke and mentos  Tear up aluminum foil  Invisible ink – Write a message on a piece of paper using phenolphthalein and spray with Windex once dried and it turns purple.  Incinerating gummy bear.  Corn starch and water.  MAGIC DUST FIRE BALL – Lycopodium powder.  Make slime – borax and glue  Bit of ethanol in a large flask, shake up, pour out excess alcohol, dry top, seal with stopper, light a flint stick or candle and light the top of the flask. Flames will travel down the length of the flask.