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Mixtures and Pure Substances

Uploaded: 6 years ago
Contributor: bio_man
Category: General Science
Type: Lecture Notes
Rating: (1)
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Filename:   3c Mixtures and Pure Substances.pptx (4.55 MB)
Page Count: 19
Credit Cost: 6
Views: 165
Last Download: N/A
Transcript
Mixtures and Pure Substances All matter is either a pure substance or a mixture Physical and chemical properties show us whether a substance is “pure” or a mixture Pure Substances Made of only ONE kind of matter Has a unique set of properties   May be either an element or a compound Element Material that cannot be broken down into any simpler substance Are the basic building blocks for all compounds Hydrogen (H) ; Carbon (C) ; Oxygen (O) Compound Combination of two or more elements in a fixed proportion When elements combine in specific proportions, they form a compound Water (H2O) ; Carbon Dioxide (CO2) Mixtures Combination of pure substances However: substances in a mixture do not combine chemically as happens when a compound is formed There are 4 main types of mixtures Mechanical mixtures Different substances that make up the mixture are visible Also called heterogeneous mixture Example: soil; package of mixed vegetables Solution Different substances that make it up are not separately visible One substance is dissolved in another Example: sugar in coffee; gas dissolved in liquid (Carbonated pop) Did you Know? Chemist call a substance dissolved in water an aqueous solution Suspension Is a cloudy mixture in which tiny particles of one substance are held within another Can be separated when poured through a filter Example: Tomato juice Colloid Also a cloudy mixture The particles of the suspended substance are so small that they cannot be easily separated out from the other substance Example: Milk; Ketchup Matter Pure Substance Mixtures Elements Compounds Solutions Mechanical Mixtures Colloid Suspension Observing Change in Matter Matter can undergo two types of change   Physical Change One in which a material changes from one state to another Material can also physically change back into its original state Chemical Change Occurs when two or more materials react and create new materials New materials have completely different properties Evidence of Chemical Change Change in Colour Change in Odour Formation of a solid or gas Release or absorption of energy Freeze Drying Food Food is Frozen-water turns into ice Frozen food up in a pressure- pressure reduced until solid turns to gas Leaves food 10% original mass & does not have to be refrigerated Meal, Ready to Eat Uses freeze dried food in a special package called a “Flameless Ration Heater” Good for Soldiers, astronauts, mountain climbers Corn based Products used by Humans Chemical made from corn can be used to make soda pop bottles, remove paint, nail polish, fuel for cars Products are not as harmful to the environment, renewable form of fuel Difference between Chemical and Physical Change Physical Change is a change in state, can be reversed Chemical Change there is a change in properties, new substance formed. Event Changes in Matter Observable Change Type of Change Baking Bread     Burning Wood     Freezing Water     Mixing sugar and Water     Evidence of Chemical change   -Change in Colour -Change in Odour -Formation of a solid or gas -Release or absorption of heat energy

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