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1 Chapter 2 Matter and Change Charles Page High School Dr. Stephen L. Cotton.

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Presentation on theme: "1 Chapter 2 Matter and Change Charles Page High School Dr. Stephen L. Cotton."— Presentation transcript:

1 1 Chapter 2 Matter and Change Charles Page High School Dr. Stephen L. Cotton

2 2 Section 2.1 Matter OBJECTIVES: OBJECTIVES: –Identify the characteristics of matter and substances.

3 3 Section 2.1 Matter OBJECTIVES: OBJECTIVES: –Differentiate among the three states of matter.

4 4 Section 2.1 Matter OBJECTIVES: OBJECTIVES: –Define physical property, and list several common physical properties of substances.

5 5 What is Matter? Matter is anything that takes up space and has mass. Matter is anything that takes up space and has mass. Mass- amount of material or stuff in an object Mass- amount of material or stuff in an object Weight is due to gravity, and changes from location to location; mass is always constant. Weight is due to gravity, and changes from location to location; mass is always constant.

6 6 Types of Matter Substance- a particular kind of matter - pure; is uniform (all the same) and has a definite composition (examples are elements & compounds) Substance- a particular kind of matter - pure; is uniform (all the same) and has a definite composition (examples are elements & compounds) –water; gold; lemonade? Mixture- more than one kind of matter; has a variable composition Mixture- more than one kind of matter; has a variable composition

7 7 Properties Words that describe matter (adjectives) Words that describe matter (adjectives) Physical Properties- a property that can be observed and measured without changing the composition. Physical Properties- a property that can be observed and measured without changing the composition. Examples- color, hardness, m.p., b.p. Examples- color, hardness, m.p., b.p. Chemical Properties- a property that can only be observed by changing the composition of the material. Chemical Properties- a property that can only be observed by changing the composition of the material.

8 8 States of matter Solid- matter that can not flow (definite shape) and has definite volume. Solid- matter that can not flow (definite shape) and has definite volume. Liquid- definite volume but takes the shape of its container (flows). Liquid- definite volume but takes the shape of its container (flows). Gas- a substance without definite volume or shape and can flow. Gas- a substance without definite volume or shape and can flow. Vapor- a substance that is currently a gas, but normally is a liquid or solid at room temperature. (water vapor?) Vapor- a substance that is currently a gas, but normally is a liquid or solid at room temperature. (water vapor?)

9 9 States of Matter Solid Liquid Gas Definite Volume? YES NO Definite Shape? YES NO Temp. increase Small Expans. Large Expans. Com- pressible? NO YES

10 10 Solid Liquid Gas Melt Evaporate Condense Freeze

11 11 Physical Changes A change that changes appearances, without changing the composition. A change that changes appearances, without changing the composition. Ex. Boil, melt, cut, bend, split, crack Ex. Boil, melt, cut, bend, split, crack Boiled water is still water. Boiled water is still water. Chemical changes - a change where a new form of matter is formed. Chemical changes - a change where a new form of matter is formed. Ex. Rust, burn, decompose, ferment Ex. Rust, burn, decompose, ferment

12 12 Section 2.2 Mixtures OBJECTIVES: OBJECTIVES: –Categorize a sample of matter as a substance or a mixture.

13 13 Section 2.2 Mixtures OBJECTIVES: OBJECTIVES: –Distinguish between homogeneous and heterogeneous samples of matter.

14 14 Mixtures Physical blend of at least two substances; variable composition Physical blend of at least two substances; variable composition Heterogeneous- mixture is not uniform in composition Heterogeneous- mixture is not uniform in composition Chocolate chip cookie, gravel, soil. Chocolate chip cookie, gravel, soil. Homogeneous- same composition throughout; called solutions Homogeneous- same composition throughout; called solutions Kool-aid, air, salt water Kool-aid, air, salt water Every part keeps its own properties. Every part keeps its own properties.

15 15 Solutions Homogeneous mixture Homogeneous mixture Mixed molecule by molecule Mixed molecule by molecule Can occur between any state of matter Can occur between any state of matter –Table 2.3, page 33 –gas in gas; liquid in gas; gas in liquid; solid in liquid; solid in solid (alloys), etc.

16 16 Solutions Like all mixtures, they keep the properties of the components. Like all mixtures, they keep the properties of the components. Some can be separated easily by physical means: rocks and marbles, iron filings and sulfur Some can be separated easily by physical means: rocks and marbles, iron filings and sulfur Other methods: distillation- takes advantage of different boiling points Other methods: distillation- takes advantage of different boiling points

17 17 Section 2.3 Elements and Compounds OBJECTIVES: OBJECTIVES: –Explain the differences between an element and a compound.

18 18 Section 2.3 Elements and Compounds OBJECTIVES: OBJECTIVES: –Identify the chemical symbols of common elements, and name common elements given their symbols.

19 19 Substances Elements- simplest kind of matter Elements- simplest kind of matter cannot be broken down any simpler cannot be broken down any simpler all one kind of atom. all one kind of atom. Compounds are substances that can be broken down only by chemical methods Compounds are substances that can be broken down only by chemical methods When broken down, the pieces have completely different properties than the original compound. When broken down, the pieces have completely different properties than the original compound. Made of two or more atoms, chemically combined (not physical blend!) Made of two or more atoms, chemically combined (not physical blend!)

20 20 Compound or Mixture CompoundMixture Made of one kind of material Made of more than one kind of material Made by a chemical change Made by a physical change Definite composition Variable composition

21 21 Which is it? Element Compound Mixture

22 22 Chemical Symbols & Formulas Currently, there are 115 elements Currently, there are 115 elements Each has a 1 or two letter symbol Each has a 1 or two letter symbol First letter always capitalized; the second never; chemical shorthand First letter always capitalized; the second never; chemical shorthand Dont need to memorize all of them; know Table A.3 inside back cover Dont need to memorize all of them; know Table A.3 inside back cover Some from Latin or other languages; note Table 2.4, page 40 Some from Latin or other languages; note Table 2.4, page 40

23 23 Section 2.4 Chemical Reactions OBJECTIVES: OBJECTIVES: –Differentiate between physical and chemical changes in matter.

24 24 Section 2.4 Chemical Reactions OBJECTIVES: OBJECTIVES: –Apply the Law of Conservation of Mass.

25 25 Chemical Reactions When one or more substances are changed into new substances. When one or more substances are changed into new substances. Reactants- stuff you start with Reactants- stuff you start with Products- What you make Products- What you make ability to undergo chemical reaction is called a chemical property ability to undergo chemical reaction is called a chemical property products have NEW PROPERTIES products have NEW PROPERTIES Arrow from reactants to products Arrow from reactants to products

26 26 Indications of a chemical reaction: Energy absorbed or released (temperature changes hotter or colder) Energy absorbed or released (temperature changes hotter or colder) Color change Color change Gas production (bubbling, fizzing, or odor change) Gas production (bubbling, fizzing, or odor change) formation of a precipitate- a solid that separates from solution (wont dissolve) formation of a precipitate- a solid that separates from solution (wont dissolve) Irreversibility- not easily reversed Irreversibility- not easily reversed

27 27 Law of Conservation of Mass Mass can not be created or destroyed in ordinary (not nuclear) chemical reactions or physical change Mass can not be created or destroyed in ordinary (not nuclear) chemical reactions or physical change All the mass can be accounted for. All the mass can be accounted for. –Burning of wood results in products that appear to have less mass as ash; where is the rest?


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