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Dr. Childs Fall, 2005 Science Laboratory Matter and Changes in Matter.

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Presentation on theme: "Dr. Childs Fall, 2005 Science Laboratory Matter and Changes in Matter."— Presentation transcript:

1 Dr. Childs Fall, 2005 Science Laboratory Matter and Changes in Matter

2 Matter

3 Matter is everything that we see and many of the things we don’t see (as air). By definition matter has mass and occupies space. Matter is classified into two major categories: - Pure substances - Mixtures Pure silver Brass (mixture of copper & zinc)

4 Matter Matter can be changed. These changes may involve physical changes in which the composition of the matter is not changed or chemical changes in which the composition is changed. Ice melting Candle burning

5 Pure Substances Pure substances: - contain the same type of particles throughout. - have a definite composition. - may be either elements or compounds - sodium Na sodium chloride NaCl chlorine Cl

6 Types of Matter Matter Substance ElementCompound Mixture HomogeneousHeterogeneous

7 Elements & Compounds

8 An element is a pure substance that cannot be broken into anther substance (by ordinary chemical means). Composed of only a single type of atom. A compound is a pure substance composed by two or more elements How about some examples?

9 Many things are made of elements. For example, aluminum is used for foil and for building cars and trailers. Elements Note: If its on the periodic table its an element!

10 Elements Gold Lead Sulfur Oxygen Sodium lamp Hydrogen fuel

11 Elements magnesium wheels chromium wheels silicon sealant lithium grease carbon fiber titanium clubs

12 Compounds Compounds are formed when two or more atoms of two or more elements combine chemically (bonding!). - fixed ratio of elements with a definite formula - separation into elements requires chemical procedures Water H 2 O Note: Compounds are NOT on the periodic table.

13 Compounds table salt NaCl table sugar C 6 H 12 O 6 Carbon dioxide CO 2 Nitrous oxide N 2 O rust Fe 2 O 3 Epsom salts MgSO 4 Sodium hydroxide NaOH

14 Mixtures

15 Mixtures are materials made up of two or more pure substances. Mixtures can be separated by physical means based on physical properties: evaporationfiltration floatingmagnets Mixtures may be either homogeneous (solutions) heterogeneous

16 Mixtures Mixture Homogeneous Evenly mixed Heterogeneous Unevenly mixed

17 Mixtures Homogeneous mixture of metal are “alloys”. Alloys include brass, steel, and white gold. Homogeneous mixtures in which one substance is dissolved in another is a “solution”. Solutions include coffee, IV fluids, and fog.

18 Examples: Sea water water and salt Coffeecoffee, sugar, cream Blood red cells, white cells, plasma Air nitrogen, oxygen, CO 2 Brasscopper, zinc White goldgold, silver, platinum Homogeneous Mixtures

19 Brass Coffee Blood colored water Corn flakes Salt water jello Homogeneous Mixtures

20 Examples: raisin bran cereal with raisins chocolate chip cookie tossed saladlettuce, tomatoes, carrots pizza pizza with meat, cheese granitefeldspar, mica Italian dressingoil, water, spice Heterogeneous Mixtures

21 Raisin Bran Granite Marble Muddy water Tossed salad Heterogeneous Mixtures Italian dressing Chocolate Chip cookie

22 Separating Mixtures evaporation salt ponds evaporation filtration distillation

23 Separating Mixtures chromatography electrophoresis centrifugation

24 Physical and Chemical Changes

25 Physical & Chemical Properties Be sure to know the difference between: - Physical properties & chemical properties - Physical changes & chemical changes

26 Physical Properties Physical properties can be observed without a chemical reaction. Examples: color: water is clear, table salt is white density: aluminum has a density of 2.7 g/cm 3 state: oxygen is a gas at room temperature magnetism: iron is attracted to magnet texture: gold is shiny

27 Physical Properties What are some physical properties of: sulfur? lemonade? dish soap?

28 Physical Changes In a physical change substances are not altered chemically, including: state changes solid  liquid liquid  gas mixing or separating adding sugar to coffee evaporating sea water for salt tearing paper

29 Physical Changes State Changes liquid  solid“freezing” water to ice liquid  gas “evaporation” water to steam gasoline to vapor solid  gas“sublimation”dry ice to CO 2 freezing evaporation sublimation

30 Physical Changes State Changes solid  liquid“melting” ice to water ice cream melting gas  liquid “condensation” ice to water melting condensation

31 Physical Changes Planing wood Physical changes may involve changing shape but not composition; Sawing wood Breaking glass

32 Chemical Properties Chemical properties: The properties of an element or compound in a chemical reaction Examples: gasoline is flammable water can be separated by electrolysis neon is inert

33 Chemical changes Chemical reactions: - yield new substances - usually cannot be easily reversed - may either require or release energy (light, heat, etc.) Sugars in wood may be split by burning. Combustion yields new substances: CO 2 and water and heat and light energy.

34 Chemical Changes Toasting bread Fireworks Candle burning Digesting food Combustion

35 Chemical Changes photosynthesis bread rising food cooking rustingbatteries

36 The End

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