Warm UpWarm Up

• How do the arrangement and How do the arrangement and behavior of particles of matter differ behavior of particles of matter differ in solids, liquids, and gases?in solids, liquids, and gases?

Unit 3Unit 3Matter/ChangeMatter/Change

Classification of MatterClassification of Matter

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)

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.

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.

Energy can exist in these Energy can exist in these forms:forms:• Radiant: light energyRadiant: light energy

– sunlightsunlight

• Chemical: stored in bonds of moleculesChemical: stored in bonds of molecules– Fuels, foodFuels, food

• Nuclear: stored within the nucleus of Nuclear: stored within the nucleus of atomsatoms

• Electrical: Flowing electrons in a current.Electrical: Flowing electrons in a current.

Energy can exist in these Energy can exist in these forms:forms:

• Mechanical: moving machine parts or Mechanical: moving machine parts or bodybody– (you can think of your(you can think of your– body as a machine too)body as a machine too)

• Thermal: heatThermal: heat– Friction causes machine parts to heat upFriction causes machine parts to heat up

Thermal EnergyThermal Energy

• Can be transported via 3 possible Can be transported via 3 possible pathwayspathways

ConvectionConvection

• The transfer of heat energy in a The transfer of heat energy in a gasgas or or liquidliquid (not in solids) by movement (not in solids) by movement of currents. of currents. – The heat move with the fluid.The heat move with the fluid.

• ExampleExample– The beach – hot air rises, cooler air from The beach – hot air rises, cooler air from

the ocean comes into replace it, and the ocean comes into replace it, and then the cool breeze cools your body.then the cool breeze cools your body.

ConductionConduction

• The transfer of heat energy The transfer of heat energy through through matter matter from particle to particle.from particle to particle.– Material are Material are actually touchingactually touching!!– Most effective in solids, but can happen in Most effective in solids, but can happen in

fluids.fluids.

• ExampleExample– Beaker on a hot plate becomes warmer Beaker on a hot plate becomes warmer

because the heat from the hot plate is because the heat from the hot plate is conducted along the beaker.conducted along the beaker.

RadiationRadiation

• The transfer of heat energy by The transfer of heat energy by electromagnetic waveselectromagnetic waves – Only form that can occur in empty space Only form that can occur in empty space

without the aid of Solids, Liquids, or without the aid of Solids, Liquids, or GasesGases

• ExampleExample– Sunlight –travels through space via Sunlight –travels through space via

radiation.radiation.

What is the way that thermal What is the way that thermal energy is transported in the energy is transported in the following?following?• Your leg becomes warn when you Your leg becomes warn when you

place a heating pad on it.place a heating pad on it.Conduction

What is the way that thermal What is the way that thermal energy is transported in the energy is transported in the following?following?

• The pilot light in your car illuminates The pilot light in your car illuminates a map.a map.

Radiation

What is the way that thermal What is the way that thermal energy is transported in the energy is transported in the following?following?

• Hot soup transfers heat to the air above it.Hot soup transfers heat to the air above it.

Convection

• The various forms of energy can be The various forms of energy can be converted into one anotherconverted into one another– Radiant E: SunlightRadiant E: Sunlight

– Chemical E: glucose produced in plants Chemical E: glucose produced in plants via photosynthesisvia photosynthesis

– Mechanical E: rabbit eats plant and Mechanical E: rabbit eats plant and metabolizes them to release energy for metabolizes them to release energy for hopping.hopping.

Try this one:Try this one:• Trace the conversion of energy from Trace the conversion of energy from

sunlight to a person riding a bicycle. sunlight to a person riding a bicycle. radiant E:

chemical E:

mechanical E: