Unit 1Unit 1Matter/ChangeMatter/Change

Classification of MatterClassification of Matter

Physical PropertyPhysical Property

• ExtensiveExtensive– Depends on amount of matter presentDepends on amount of matter present

•Mass Mass •VolumeVolume

• IntensiveIntensive– Does Does notnot depend on the amount of depend on the amount of

matter presentmatter present•ColorColor•Phase Phase •Density (mass/volume)Density (mass/volume)

Chemical Property

• Only observed when there is a change in the composition of the substance

•Ability of a substance to react with other substances or to decompose.

What is matter?What is matter?

• Has a massHas a mass

• Takes up spaceTakes up space

States of MatterStates of Matter

• SolidSolid– Has a rigid, definite shapeHas a rigid, definite shape– The atoms, ions, or molecules that make The atoms, ions, or molecules that make

up a solid are fixed in placeup a solid are fixed in place

States of MatterStates of Matter

• LiquidLiquid– Has an indefinite shapeHas an indefinite shape– Is flowing matter with Is flowing matter with

definite volumedefinite volume– Takes the shape of its Takes the shape of its

containercontainer– Particles of a liquid can Particles of a liquid can

move and easily glide over move and easily glide over each othereach other

States of MatterStates of Matter

• GasGas– Has no definite shapeHas no definite shape– Has no definite Has no definite

volumevolume– Is compressible Is compressible

mattermatter– Particles of gas are Particles of gas are

much farther apart much farther apart and are easily and are easily pushed togetherpushed together

Matter

Pure Substance MixturesUniform/Definite composition

One Chemical Formula

2 or more substances physically combined

Element Compound

One type of atom

Found on Period Table

2 or more elements

chemically combined

Homogeneous Heterogeneous

Solutions

Uniform throughout

Not uniform through out.

Matter/Change

Physical/Chemical Changes

Physical Property

• Characteristics that a sample of matter exhibits WITHOUT any change to its identity.

Physical ChangePhysical Change

• A change that A change that does notdoes not produce a produce a new substance!new substance!

New

Substance

Examples:Examples:

• SolubilitySolubility• Melting/Boiling PointMelting/Boiling Point• Phase ChangePhase Change• Size/Shape ChangeSize/Shape Change• It’s Color (It’s Color (notnot change in) change in)• DensityDensity• Electrical ConductivityElectrical Conductivity• Physical State (solid, Liquid, or gas)Physical State (solid, Liquid, or gas)

Chemical ChangeChemical Change

• A change that A change that doesdoes produce a new produce a new substance (chemical reaction)substance (chemical reaction)

• ““Can the change be reversed?”Can the change be reversed?” – If If yesyes: probably : probably physicalphysical. . – If If nono, probably , probably chemicalchemical..

• Example: Example: Milk goes sourMilk goes sour..– Can the change be reversed?Can the change be reversed? NO.NO. – You cannot get the milk to taste good again. So it is a You cannot get the milk to taste good again. So it is a

chemical change. Note that a new substance (lactic acid) chemical change. Note that a new substance (lactic acid) has been produced. This acid is formed when bacteria break has been produced. This acid is formed when bacteria break down the lactose in the milk. down the lactose in the milk.

• Example: Example: An ice cube meltsAn ice cube melts.. – Can the change be reversed?Can the change be reversed? YES.YES. – Just put the water back in the freezer. Note that no new Just put the water back in the freezer. Note that no new

substance is produced. Phase changes (changes between substance is produced. Phase changes (changes between states of matter—solid, liquid, gas) are NOT chemical states of matter—solid, liquid, gas) are NOT chemical changes! changes!

This rule is not perfect; it is just meant as a This rule is not perfect; it is just meant as a guide.guide.

Physical vs. Chemical Physical vs. Chemical ChangesChanges

Chemical Change-Look for:Chemical Change-Look for:• Formation of a gas (odor)Formation of a gas (odor)

• Light producedLight produced

• Formation of precipitateFormation of precipitate

• Change in temperatureChange in temperature– (gets hot—exothermic* or cold—

endothermic**)

• Permanent ChangePermanent Change in color in color

Matter/ChangeMatter/Change

EnergyEnergy

Law of Conservation of MatterLaw of Conservation of Matter

Law of Conservation of Mass Law of Conservation of Mass (Matter)(Matter)

• Matter can be neither created nor Matter can be neither created nor destroyed.destroyed.– Original atoms in reactants may Original atoms in reactants may

move around, but will be found on move around, but will be found on the product side.the product side.

2 2 6 12 6 26 6 6CO H O C H O O How many atoms of carbon are on the reactant side?

On the product side?

How many H on the reactant side?

On the product side?

How many O on the reactant side?

On the product side?

66

12

12

18

18

Don’t need to write!

2 2 6 12 6 26 6 6CO H O C H O O

264 108 180 192g g g g The mass of the reactants must equal the mass of the products!!

Reactants = Products

372g = 372g

ExothermicExothermic

•The chemical reaction The chemical reaction releases heat energy to the releases heat energy to the surroundings.surroundings.

4 2 2 22 2CH O CO H O energy

EndothermicEndothermic

2 2 22 2H O energy H O The chemical reaction absorbs heat energy from the surroundings.

Energy ChangesEnergy Changes

•What is energy?What is energy?– The capacity to do work.The capacity to do work.

Two Types of EnergyTwo Types of Energy

• PotentialPotential– Energy of position.Energy of position.– Stored energy in bonds of molecules.Stored energy in bonds of molecules.

ExampleExample

• Gasoline stored at a gas stationGasoline stored at a gas station

Two types of energyTwo types of energy

• KineticKinetic– Energy in motionEnergy in motion

ExampleExample

• Moving cars as they go down the road. As the Moving cars as they go down the road. As the gasoline is burned, energy is released from the gasoline is burned, energy is released from the bonds and is used to power the car’s engine.bonds and is used to power the car’s engine.

Energy ConversionsEnergy Conversions

• Law of Conservation of EnergyLaw of Conservation of Energy– Energy can be Energy can be convertedconverted from one form to from one form to

another, but it is not created or destroyed.another, but it is not created or destroyed.

Metals

NonmetalsMetalloids

Metals

NonmetalsMetalloids

Properties of MetalsProperties of Metals• Metals are good Metals are good

conductors of heat and conductors of heat and electricity.electricity.

• Metals are shiny.Metals are shiny.• Metals are ductile (can be Metals are ductile (can be

stretched into thin wires).stretched into thin wires).• Metals are malleable (can Metals are malleable (can

be pounded into thin be pounded into thin sheets).sheets).

• A chemical property of A chemical property of metal is its reaction with metal is its reaction with water which results in water which results in corrosion.corrosion.

Properties of Non-MetalsProperties of Non-Metals• Non-metals are poor Non-metals are poor

conductors of heat conductors of heat and electricity.and electricity.

• Non-metals are not Non-metals are not ductile or malleable.ductile or malleable.

• Solid non-metals are Solid non-metals are brittle and break brittle and break easily.easily.

• They are dull.They are dull.• Many non-metals are Many non-metals are

gases.gases.

Sulfur

Properties of MetalloidsProperties of Metalloids• Metalloids (metal-like) Metalloids (metal-like)

have properties of both have properties of both metals and non-metals.metals and non-metals.

• They are solids that can They are solids that can be shiny or dull.be shiny or dull.

• They conduct heat and They conduct heat and electricity better than electricity better than non-metals but not as non-metals but not as well as metals.well as metals.

• They are ductile and They are ductile and malleable.malleable.

Silicon

• Columns of elements are Columns of elements are called groups or families. called groups or families.

• Elements in each family Elements in each family have similar but not have similar but not identical properties.identical properties.

• For example, lithium (Li), For example, lithium (Li), sodium (Na), potassium (K), sodium (Na), potassium (K), and other members of family and other members of family 1 are all soft, white, shiny 1 are all soft, white, shiny metals.metals.

• All elements in a family have All elements in a family have the same number of valence the same number of valence electrons.electrons.

• Each horizontal row of elements is called a period.Each horizontal row of elements is called a period.• The elements in a period are not alike in properties.The elements in a period are not alike in properties.• In fact, the properties change greatly across even In fact, the properties change greatly across even

given row.given row.• The first element in a period is always an extremely The first element in a period is always an extremely

active solid. The last element in a period, is always active solid. The last element in a period, is always an inactive gas.an inactive gas.