Presentation on theme: "Chapter 2 Matter and Change"— Presentation transcript:
1Chapter 2 Matter and Change Charles Page High SchoolDr. Stephen L. Cotton
2Section 2.1 Matter OBJECTIVES: Identify the characteristics of matter and substances.
3Section 2.1 Matter OBJECTIVES: Differentiate among the three states of matter.
4Section 2.1 Matter OBJECTIVES: Define physical property, and list several common physical properties of substances.
5What is Matter? Matter is anything that takes up space and has mass. Mass- amount of material or “stuff” in an objectWeight is due to gravity, and changes from location to location; mass is always constant.
6Types of MatterSubstance- 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
7Properties Words that describe matter (adjectives) Physical Properties- a property that can be observed and measured without changing the composition.Examples- color, hardness, m.p., b.p.Chemical Properties- a property that can only be observed by changing the composition of the material.
8States of matterSolid- matter that can not flow (definite shape) and has definite volume.Liquid- definite volume but takes the shape of its container (flows).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?)
11Physical ChangesA change that changes appearances, without changing the composition.Ex. Boil, melt, cut, bend, split, crackBoiled water is still water.Chemical changes - a change where a new form of matter is formed.Ex. Rust, burn, decompose, ferment
12Section 2.2 Mixtures OBJECTIVES: Categorize a sample of matter as a substance or a mixture.
13Section 2.2 Mixtures OBJECTIVES: Distinguish between homogeneous and heterogeneous samples of matter.
14MixturesPhysical blend of at least two substances; variable compositionHeterogeneous- mixture is not uniform in compositionChocolate chip cookie, gravel, soil.Homogeneous- same composition throughout; called “solutions”Kool-aid, air, salt waterEvery part keeps it’s own properties.
15Solutions Homogeneous mixture Mixed molecule by molecule Can occur between any state of matterTable 2.3, page 33gas in gas; liquid in gas; gas in liquid; solid in liquid; solid in solid (alloys), etc.
16SolutionsLike all mixtures, they keep the properties of the components.Some can be separated easily by physical means: rocks and marbles, iron filings and sulfurOther methods: distillation- takes advantage of different boiling points
17Section 2.3 Elements and Compounds OBJECTIVES:Explain the differences between an element and a compound.
18Section 2.3 Elements and Compounds OBJECTIVES:Identify the chemical symbols of common elements, and name common elements given their symbols.
19Substances Elements- simplest kind of matter cannot be broken down any simplerall one kind of atom.Compounds are substances that can be broken down only by chemical methodsWhen broken down, the pieces have completely different properties than the original compound.Made of two or more atoms, chemically combined (not physical blend!)
20Compound or Mixture Compound Mixture Made of one kind of material Made of more thanone kind of materialMade by achemical changephysical changeDefinitecompositionVariable
22Chemical Symbols & Formulas Currently, there are 115 elementsEach has a 1 or two letter symbolFirst letter always capitalized; the second never; chemical “shorthand”Don’t need to memorize all of them; know Table A.3 inside back coverSome from Latin or other languages; note Table 2.4, page 40
23Section 2.4 Chemical Reactions OBJECTIVES:Differentiate between physical and chemical changes in matter.
24Section 2.4 Chemical Reactions OBJECTIVES:Apply the Law of Conservation of Mass.
25Chemical ReactionsWhen one or more substances are changed into new substances.Reactants- stuff you start withProducts- What you makeability to undergo chemical reaction is called a chemical propertyproducts have NEW PROPERTIESArrow from reactants to products
26Indications of a chemical reaction: Energy absorbed or released (temperature changes hotter or colder)Color changeGas production (bubbling, fizzing, or odor change)formation of a precipitate- a solid that separates from solution (won’t dissolve)Irreversibility- not easily reversed
27Law of Conservation of Mass Mass can not be created or destroyed in ordinary (not nuclear) chemical reactions or physical changeAll the mass can be accounted for.Burning of wood results in products that appear to have less mass as ash; where is the rest?