1. CHAPTER 17 COMPOSITION AND PROPERTIES OF MATTER

2. ATOMS 1. Most basic unit of matter 2. Cannot be broken down into smaller units 3. Building blocks of the universe 4. About 100 naturally occurring atoms 5. Each kind is called an element 1. Most basic unit of matter 2. Cannot be broken down into smaller units 3. Building blocks of the universe 4. About 100 naturally occurring atoms 5. Each kind is called an element

3. SUBSTANCE 1. An element or a compound a. When all atoms in a substance are alike, the substance is an element 1. Any element on the periodic table b. A compound is a substance with two or more elements combined in a fixed proportion 1. An element or a compound a. When all atoms in a substance are alike, the substance is an element 1. Any element on the periodic table b. A compound is a substance with two or more elements combined in a fixed proportion

4. Examples of common compounds: salt: NaCl water: H 2 O sugar: C 12 H 22 O 11 carbon dioxide: CO 2 hydrogen peroxide: H 2 O 2 vinegar: HC 2 H 3 O 3 baking soda: NaHCO 3 Examples of common compounds: salt: NaCl water: H 2 O sugar: C 12 H 22 O 11 carbon dioxide: CO 2 hydrogen peroxide: H 2 O 2 vinegar: HC 2 H 3 O 3 baking soda: NaHCO 3

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6. MIXTURES 1. Homogeneous: mixture that contains two or more substances blended evenly throughout Examples: kool-aid, perfume, sodas a. Solution: a homogeneous mixture with particles so small that they cannot be seen with a microscope, and will not settle out of solution 1. Homogeneous: mixture that contains two or more substances blended evenly throughout Examples: kool-aid, perfume, sodas a. Solution: a homogeneous mixture with particles so small that they cannot be seen with a microscope, and will not settle out of solution

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8. 2. Heterogeneous: all parts are not evenly mixed together and parts are easily identified Examples: salad, seasoning mix, shells and sand, chex mix 2. Heterogeneous: all parts are not evenly mixed together and parts are easily identified Examples: salad, seasoning mix, shells and sand, chex mix

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10. a. Colloid: heterogeneous mixture with larger particles that never settle; colloids scatter light 1. Examples: fog, smoke, paint, jell-o b. Suspension: heterogeneous mixture containing a liquid in which visible particles settle 1. Example: pond water a. Colloid: heterogeneous mixture with larger particles that never settle; colloids scatter light 1. Examples: fog, smoke, paint, jell-o b. Suspension: heterogeneous mixture containing a liquid in which visible particles settle 1. Example: pond water

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13. PHYSICAL PROPERTIES 1. Characteristics of a material that can be observed without changing the identity of the material a. Examples: size, shape, color, density, temperature, melting and boiling points 1. Characteristics of a material that can be observed without changing the identity of the material a. Examples: size, shape, color, density, temperature, melting and boiling points

14. PHYSICAL CHANGES 1. When matter undergoes a change in size, shape, or phase; the particles that make up the matter do not change 2. Examples: freezing or melting water, weathering and erosion of rocks, cutting a tree down, tearing paper 1. When matter undergoes a change in size, shape, or phase; the particles that make up the matter do not change 2. Examples: freezing or melting water, weathering and erosion of rocks, cutting a tree down, tearing paper

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16. CHEMICAL PROPERTIES 1. Characteristics of a substance indicating that it can change chemically a. Examples: flammability, light sensitivity of a substance 1. Characteristics of a substance indicating that it can change chemically a. Examples: flammability, light sensitivity of a substance

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18. CHEMICAL CHANGES 1. Particles of one substance are changed in some way to form particles of a new substance that has new and different properties 2. There may be: Production of heat or light Appearance of gas bubbles Formation of a solid 1. Particles of one substance are changed in some way to form particles of a new substance that has new and different properties 2. There may be: Production of heat or light Appearance of gas bubbles Formation of a solid

19. 3. Examples: rust on an iron nail, lightning bug’s light, oxygen being released during photosynthesis, baking a cake, perming or coloring your hair

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21. CONSERVATION OF MASS The mass of all substances present before a chemical change equals the mass of all substances after the chemical change

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