Chapter 2 Section 2 NotesChapter 2 Section 2 Notes

Matter and EnergyMatter and Energy

Kinetic Theory of Matter: Useful for Useful for seeingseeing differences in the 3 differences in the 3

common states of matter on earth: common states of matter on earth: solidsolid, , liquidliquid, and , and gasgas. .

Kinetic Theory of Matter3 Main Points1.1. All matter is made of atoms and All matter is made of atoms and

molecules which act like tiny molecules which act like tiny particles that are always in motion.particles that are always in motion.

2.2. The higher the temperature, the The higher the temperature, the faster the particles move. faster the particles move.

3.3. At the same temperature, heavier At the same temperature, heavier particles move slower than lighter particles move slower than lighter particles. particles.

States of Matter Solid: particles are in a Solid: particles are in a fixedfixed position position

rigid structurerigid structure; no freedom to change ; no freedom to change positionspositions

Particles are held closely together by Particles are held closely together by strong attractionsstrong attractions

Diagram: Diagram:

Liquid Liquid: particles are closely packed, Liquid: particles are closely packed,

but can but can still slide past each otherstill slide past each other Take the shape of their Take the shape of their containercontainer Particles are close but Particles are close but not as close as a not as close as a

solidsolid Particles can move Particles can move randomlyrandomly and and spreadspread

on their ownon their own Diagram:Diagram:

Viscosity: Viscosity: Viscosity: resistance of a fluid to flowresistance of a fluid to flow

syrupsyrup is more viscous than is more viscous than waterwater Determined by the attraction of Determined by the attraction of

particles: particles: the stronger the attraction, the the stronger the attraction, the more viscous (thick) the liquid is. more viscous (thick) the liquid is.

Gas Gas: particles are in a Gas: particles are in a constant state constant state

of motionof motion and and rarely stick togetherrarely stick together expand to fill available spacesexpand to fill available spaces

Example: scents of food or perfumeExample: scents of food or perfume Diagram:Diagram:

Gas A balloon filled with helium is under A balloon filled with helium is under

pressure: pressure: Pressure: force exerted per Pressure: force exerted per unit area of a substanceunit area of a substance If there is too much pressure (too many If there is too much pressure (too many

helium particles) in a balloon, what helium particles) in a balloon, what happens?happens?

A gas under pressure will escape the A gas under pressure will escape the container if possible.container if possible. Think about an air Think about an air filled balloon that you let go.filled balloon that you let go.

Kinetic Theory Using the Kinetic Theory of matter, Using the Kinetic Theory of matter,

explain why a balloon filled with explain why a balloon filled with helium goes flat faster than one filled helium goes flat faster than one filled with regular air. with regular air.

Fluids Fluids: Fluids: substances that can spreadsubstances that can spread

Both Both liquidsliquids and and gasesgases can spread, so can spread, so they are considered fluids. they are considered fluids.

Plasma Plasma: most common state of matter Plasma: most common state of matter

in universe: in universe: NOT on EarthNOT on Earth Makes up 99.9 % of the universeMakes up 99.9 % of the universe Plasma is superheated gas and is a Plasma is superheated gas and is a

collection of free moving electrons and collection of free moving electrons and ions; the term came about in 1920’s to ions; the term came about in 1920’s to represent electrically charged particles represent electrically charged particles at high energyat high energy

Plasma Examples of Examples of

plasma on earthplasma on earth lightninglightning firefire

Energy Energy: Energy: the ability to change or move the ability to change or move

mattermatter Examples of energy or sources of energy:Examples of energy or sources of energy:

heat, light, spring coiling, batteriesheat, light, spring coiling, batteries Energy must be Energy must be ADDEDADDED to melt or evaporate to melt or evaporate

substancessubstances Aluminum must be melted before it can be Aluminum must be melted before it can be

recycledrecycled As aluminum particles gain heat, As aluminum particles gain heat, particles move particles move

fasterfaster and break away from fixed positions and and break away from fixed positions and become liquids: called become liquids: called meltingmelting

Energy Energy must be Energy must be RELEASEDRELEASED to make a to make a

gas become a liquid or solid again.gas become a liquid or solid again. When HWhen H22O is a gas and molecules slow O is a gas and molecules slow

down the water vapor down the water vapor returns to a liquid returns to a liquid (called condensation).(called condensation). When When moleculesmolecules slow down even more, the water goes to slow down even more, the water goes to a a solidsolid (ice). (ice).

Energy Energy relationship between solid, Energy relationship between solid,

liquid, and gas diagram:liquid, and gas diagram:

liquidliquid gasgassolidsolid

Energy ABSORBED

Energy RELEASED

Important Note: Changing the Changing the state of matterstate of matter does does

NOT NOT change the substance or mass.change the substance or mass. Water, steam, and ice are all HWater, steam, and ice are all H22O: the O: the

only change is the only change is the nature of attraction nature of attraction between moleculesbetween molecules

Phase Change Diagram:

Melting

Freezing

Condensation

Evaporation

SublimationDeposition

SolidSolid

LiquidLiquid GasGas

Phase Changes Evaporation: change of a substance from a Evaporation: change of a substance from a

liquidliquid to a to a gasgas.. Condensation: change of a substance from Condensation: change of a substance from

a a gasgas to a to a liquidliquid.. Sublimation: change of a substance from a Sublimation: change of a substance from a

solid solid to a to a gasgas.. Deposition: change of a substance from a Deposition: change of a substance from a

gasgas to a to a solidsolid Example: Example: Water vapor without becoming liquid- Water vapor without becoming liquid-

this is how snow forms in clouds. this is how snow forms in clouds.

Law of Conservation of Mass Law of Conservation of Mass: Law of Conservation of Mass: Mass Mass

cannot be created or destroyedcannot be created or destroyed Example: Example: Burning a matchBurning a match: consider : consider

what you start and end with.what you start and end with.

Trivia Question Trivia Question: If mass cannot be Trivia Question: If mass cannot be

created or destroyed, then why do we created or destroyed, then why do we have to replace our tires when the have to replace our tires when the rubber “wears away”?rubber “wears away”?

Law of Conservation of Energy Law of Conservation of Energy: Law of Conservation of Energy:

Energy cannot be created or Energy cannot be created or destroyeddestroyed EnergyEnergy can be can be convertedconverted from one form from one form

to another.to another. Example: A wristwatch: from Example: A wristwatch: from chemicalchemical

energy to energy to mechanical mechanical energy. energy.