Chemistry - Chapter 2 matter and change

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Chapter Chapter

22“Matter and “Matter and

Change”Change”

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Section 2.1Section 2.1Properties of MatterProperties of Matter

OBJECTIVES:OBJECTIVES:

–IdentifyIdentify properties of matter properties of matter as extensive or intensive.as extensive or intensive.

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–DefineDefine physical property, physical property, and and listlist several common several common physical properties of physical properties of substances.substances.

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–DifferentiateDifferentiate among three among three states of matter.states of matter.

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–DescribeDescribe a physical a physical change.change.

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MatterMatterMatter is anything that: a) Matter is anything that: a) has has

massmass, and b) , and b) takes up spacetakes up spaceMass = Mass = a measure of the amount a measure of the amount

of “stuff” (or material) the objectof “stuff” (or material) the object contains (don’t confuse this with contains (don’t confuse this with weight, a measure of gravity)weight, a measure of gravity)

Volume = Volume = a measure of the space a measure of the space occupied by the objectoccupied by the object

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Describing MatterDescribing Matter Properties used to describe matter Properties used to describe matter

can be classified as:can be classified as:

1)1) ExtensiveExtensive – – depends on the depends on the amountamount of matter in the sample of matter in the sample

- - Mass, volume, calories are examplesMass, volume, calories are examples

2)2) IntensiveIntensive – – depends on the depends on the typetype of matter, not the amount presentof matter, not the amount present

- - Hardness, Density, Boiling PointHardness, Density, Boiling Point

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Properties are…Properties are… Words that describe matter (adjectives)Words that describe matter (adjectives) Physical PropertiesPhysical Properties- - a property that can a property that can

be observed and measured without be observed and measured without changing the material’s composition.changing the material’s composition.

Examples- Examples- color, hardness, m.p., b.p.color, hardness, m.p., b.p. Chemical PropertiesChemical Properties- - a property that a property that

can only be observed by changing the can only be observed by changing the composition of the material.composition of the material.

Examples- Examples- ability to burn, decompose, ability to burn, decompose, ferment, react with, etc.ferment, react with, etc.

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States of matterStates of matter1)1) SolidSolid- - matter that can not flow (definite matter that can not flow (definite

shape) and has definite volume.shape) and has definite volume.

2)2) LiquidLiquid- - definite volume but takes the definite volume but takes the shape of its container (flows).shape of its container (flows).

3)3) GasGas- - a substance without definite volume a substance without definite volume or shape and can flow.or shape and can flow.

– VaporVapor- a substance that is currently a - a substance that is currently a gas, but normally is a liquid or solid at gas, but normally is a liquid or solid at room temperature. (Which is correct: room temperature. (Which is correct: “water gas”, or “water vapor”?)“water gas”, or “water vapor”?)

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States of MatterStates of Matter

Solid

Liquid

Gas

Definite Volume?

YES

YES

NO

Definite Shape?

YES

NO

NO

Result of a TemperatureIncrease?

Small Expans.

Small Expans.

Large Expans.

Will it Compress?

NO

NO

YES

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44thth state: state: PlasmaPlasma - - formed at formed at high temperatures; ionized high temperatures; ionized

phase of matter as found in the phase of matter as found in the sunsun

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Three Main Phases – page 41Three Main Phases – page 41

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Solid Liquid Gas

Melt Evaporate

CondenseFreeze

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Copper Phases - SolidCopper Phases - Solid

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Copper Phases - LiquidCopper Phases - Liquid

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Copper Phases – Vapor (gas)Copper Phases – Vapor (gas)

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Physical vs. Chemical ChangePhysical vs. Chemical Change Physical changePhysical change will change the visible will change the visible

appearance, without changing the appearance, without changing the composition of the material.composition of the material.– Boil, melt, cut, bend, split, crackBoil, melt, cut, bend, split, crack– Is boiled water still water?Is boiled water still water?

Can be Can be reversiblereversible, or , or irreversibleirreversible Chemical changeChemical change - - a change where a a change where a

new form of matter is formed.new form of matter is formed.– Rust, burn, decompose, fermentRust, burn, decompose, ferment

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Section 2.2Section 2.2MixturesMixtures


–CategorizeCategorize a sample of a sample of matter as a substance or a matter as a substance or a mixture.mixture.

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–DistinguishDistinguish between between homogeneous and homogeneous and heterogeneous samples of heterogeneous samples of matter.matter.

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–DescribeDescribe two ways that two ways that components of mixtures can components of mixtures can be separated.be separated.

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Mixtures are a Mixtures are a physical blendphysical blend of at of at least least twotwo substances; have variable substances; have variable composition. They can be either:composition. They can be either:

1)1) Heterogeneous Heterogeneous – – the mixture is not the mixture is not uniform in compositionuniform in composition

• Chocolate chip cookie, gravel, soil.Chocolate chip cookie, gravel, soil.2)2) Homogeneous Homogeneous - - same composition same composition

throughout; called “throughout; called “solutionssolutions””• Kool-aid, air, salt waterKool-aid, air, salt water

Every part keeps it’s own properties.Every part keeps it’s own properties.

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Solutions are homogeneous mixturesSolutions are homogeneous mixtures Mixed molecule by molecule, thus too Mixed molecule by molecule, thus too

small to see the different partssmall to see the different parts Can occur between any state of Can occur between any state of

matter: gas in gas; liquid in gas; gas matter: gas in gas; liquid in gas; gas in liquid; solid in liquid; solid in solid in liquid; solid in liquid; solid in solid (alloys), etc.(alloys), etc.

Thus, based on the distribution of Thus, based on the distribution of their components, mixtures are called their components, mixtures are called homogeneoushomogeneous or or heterogeneousheterogeneous..

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Phase?Phase? The term “phase” is used to describe The term “phase” is used to describe

any part of a sample with uniform any part of a sample with uniform composition of properties.composition of properties.

A homogeneous mixture consists of a A homogeneous mixture consists of a singlesingle phase phase

A heterogeneous mixture consists of A heterogeneous mixture consists of two or moretwo or more phases. phases.

Note Figure 2.6, page 45Note Figure 2.6, page 45

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Separating MixturesSeparating Mixtures Some can be separated easily by Some can be separated easily by

physical means: rocks and marbles, physical means: rocks and marbles, iron filings and sulfur (use magnet) iron filings and sulfur (use magnet)

Differences in physical properties Differences in physical properties can be used to separate mixtures.can be used to separate mixtures.

FiltrationFiltration - - separates a solid from separates a solid from the liquid in a heterogeneousthe liquid in a heterogeneous mixture (by size)mixture (by size) – – Figure 2.7, page 46 Figure 2.7, page 46

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Separation of a MixtureSeparation of a MixtureComponents of dyes such as ink may be separated by paper chromatography.

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Separation of a MixtureSeparation of a MixtureDistillation: takes advantage of different boiling points.

NaCl boils at 1415 oC

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Section 2.3Section 2.3Elements and CompoundsElements and Compounds


–ExplainExplain the differences the differences between an element and a between an element and a compound.compound.

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–DistinguishDistinguish between a between a substance and a mixture.substance and a mixture.

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–IdentifyIdentify the chemical the chemical symbols of elements, and symbols of elements, and namename elements given their elements given their symbols.symbols.

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Substances are either:

a) elements, or

b) compounds

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Substances: element or compoundSubstances: element or compound ElementsElements- - simplest kind of mattersimplest kind of matter

– cannot be broken down any simpler and cannot be broken down any simpler and still have properties of that element!still have properties of that element!

– all all oneone kind of atom. kind of atom. CompoundsCompounds are are substances that can be substances that can be

broken down broken down onlyonly by chemical methods by chemical methods

– when broken down, the pieces have when broken down, the pieces have completely different properties than the completely different properties than the original compound.original compound.

– made of made of two or moretwo or more atoms, chemically atoms, chemically combined (not just a physical blend!)combined (not just a physical blend!)

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Compound vs. MixtureCompound vs. Mixture

Compound Mixture

Made of one kindof material

Made of more thanone kind of material

Made by a chemical change

Made by a physical change

Definitecomposition

Variablecomposition

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Which is it?Which is it?

ElementCompoundMixture

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Elements vs. CompoundsElements vs. Compounds Compounds Compounds cancan be broken down be broken down

into simpler substances by into simpler substances by chemical means, but chemical means, but elements elements

cannotcannot.. A “A “chemical changechemical change” is a change ” is a change

that produces matter with a that produces matter with a different compositiondifferent composition than the than the original matter.original matter.

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Chemical ChangeChemical ChangeA change in which one or more substances are converted into different substances.

Heat and

light are often evidence of a chemical change.

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Properties of CompoundsProperties of Compounds Quite different properties than their Quite different properties than their

component elements.component elements. Due to a Due to a CHEMICAL CHANGECHEMICAL CHANGE, the , the

resulting compound has new and resulting compound has new and different properties:different properties:• Table sugar – Table sugar – carbon, hydrogen, carbon, hydrogen,

oxygenoxygen• Sodium chloride – Sodium chloride – sodium, chlorinesodium, chlorine• Water – Water – hydrogen, oxygenhydrogen, oxygen

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Classification of MatterClassification of Matter

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Symbols & FormulasSymbols & Formulas Currently, there are Currently, there are 118118 elements elements Elements have a 1 or two letter Elements have a 1 or two letter symbolsymbol, ,

and compounds have a and compounds have a formulaformula.. An element’s first letter always An element’s first letter always capitalizedcapitalized; ;

if there is a second letter, it is written if there is a second letter, it is written lowercaselowercase: B, Ba, C, Ca, H, He: B, Ba, C, Ca, H, He

Start learningStart learning the elements names and the elements names and symbols listed in the back of the book and symbols listed in the back of the book and in your periodic tablein your periodic table

Some names come from Latin or other Some names come from Latin or other languages; note Table 2.4, page 40languages; note Table 2.4, page 40

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Section 2.4Section 2.4Chemical ReactionsChemical Reactions


–DescribeDescribe what happens what happens during a chemical change.during a chemical change.

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–IdentifyIdentify four possible clues four possible clues that a chemical change has that a chemical change has taken place.taken place.

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–ApplyApply the law of the law of conservation of mass to conservation of mass to chemical reactions.chemical reactions.

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Chemical ChangesChemical Changes The ability of a substance to undergo The ability of a substance to undergo

a specific chemical change is called a a specific chemical change is called a chemical propertychemical property..

• iron plus oxygen forms rust, so the iron plus oxygen forms rust, so the ability to rust is a chemical property ability to rust is a chemical property of ironof iron

During a chemical change (also called During a chemical change (also called chemical reaction), chemical reaction), the composition of the composition of matter always changes. matter always changes.

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Chemical Reactions are…Chemical Reactions are… When one or more substances are When one or more substances are

changed into new substances.changed into new substances. ReactantsReactants- - the stuff you start withthe stuff you start with ProductsProducts- - what you makewhat you make The products will have The products will have NEW NEW

PROPERTIESPROPERTIES different from the different from the reactants you started withreactants you started with

Arrow points Arrow points from the reactants from the reactants toto the the new productsnew products

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Recognizing Chemical ChangesRecognizing Chemical Changes1)1) EnergyEnergy is absorbed or releasedis absorbed or released

(temperature changes hotter or colder)(temperature changes hotter or colder)

2)2) ColorColor changes changes

3)3) GasGas production production (bubbling, fizzing, or odor (bubbling, fizzing, or odor change; smoke)change; smoke)

4)4) formation of a formation of a precipitateprecipitate - a solid that - a solid that separates from solution (won’t dissolve)separates from solution (won’t dissolve)

5)5) IrreversibilityIrreversibility - not easily reversed- not easily reversed

But, there are examples of these that are not But, there are examples of these that are not chemical – boiling water bubbles, etc.chemical – boiling water bubbles, etc.

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Law of Conservation of Mass Law of Conservation of Mass During any chemical reaction, the During any chemical reaction, the

mass of the products is always equal mass of the products is always equal to the mass of the reactants.to the mass of the reactants.

All the massAll the mass can be accounted for: can be accounted for:

–Burning of wood results in products Burning of wood results in products that appear to have less mass as that appear to have less mass as ashes; where is the rest?ashes; where is the rest?

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- Page 55

reactants = product

43.43 g Original mass = 43.43 g Final mass

Chemistry - Chapter 2 matter and change

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Transcript of Chemistry - Chapter 2 matter and change