Post on 08-Oct-2019
7.1KMTandChangesinState
Matter:anythingwithmassandvolume
• Mass:quantityofmatterthatasubstanceorobjectcontains(g orkg)
• Volume:amountofspacetakenupbyasubstance(mL,L,orcm3)
ThreeStatesofMatter
Solid – definitevolumeandshape
Liquid – definitevolumeandchangingshape
Gas– changingvolumeandshape
I.ParticleModelofMatter
1)Allmatterismadeupofverysmallparticles
2)Therearespacesbetweentheparticles
3)Theparticles inmatterarealwaysmoving
4)Theparticlesareattractedtooneanother
II.KineticMolecularTheory
• Matter,chemicalchangesandthestatesofmatterareallpartofchemistry
KMT…• explainswhathappenstomatterwhenthekineticenergyofparticleschanges
*KineticEnergyistheenergyofmotion
KineticMolecularTheory…
1. Allmatterismadeupofsmallparticles
2. Thereisemptyspacebetweentheparticles
3. Particlesareconstantlymoving.Theparticlesarecollidingwitheachotherandthewallsoftheircontainer.
SOLIDS: particlesare tightlypacked;particlescannotmovearoundfreely,vibratinginplace
LIQUIDS: particlesareslightlyfurtherapart;particlescanslidebyeachother
GASES: particlesarefurtherapartandmovingquickly;particlescanmovefreely
KineticMolecularTheory…
4.Energymakesparticlesmove.Themoreenergytheparticleshave,thefastertheycanmoveandthefartheraparttheyget.
IV.ThermalExpansionandContraction• Whentemperature increases,kineticenergy
increases
• Particlesmovefasterandoveralargerregionrequiringmorespacebetweenparticles
• Substance“expands”– increasinginvolume
• Whentemperaturedecreases,kineticenergydecreases
• Particlesslowdown andtakeuplessspace
• Substance“contracts”– decreasinginvolume
V.Temperaturevs.Heat
• ThermalEnergy: totalenergyofalltheparticlesinasubstance
• Heat: thetransferofthermalenergyfromahottermaterialtoacoolerone
• Temperature: averagekineticenergyoftheparticles
• Meltingpointisthetemperatureatwhichsolidturnstoliquid.
• Boilingpointisthetemperatureatwhichliquidturnsintogas.
I.Solid,LiquidandGasDensity
• Fluid:matterthancanflow(liquidsorgases–notsolids!)
• Density: massofagivenvolume(howcloselypackedparticlesare)
• Mostsubstancesaremoredenseinsolidformthanliquidform…exceptwater
• Watermoleculesmoveslightlyapartwhentheylockintoplaceinicecrystals
• Thisiswhyicefloatsonwater
II.LayeringandMeasuringDensity
• Lessdensematerialfloatsontopofmoredensematerial
• Ifanobject:o floatsinafluid– lessdenseohoversinplace– samedensityosinksinafluid–moredense
UseDisplacementforirregularlyshapedobjects
• submergeobjectinafluidandmeasurethechangeofvolumeinthefluid
• thevolumeoftheobjectisthesameasthechangeinfluidvolume
2)Acarverbeginsworkonablockofgranitethatmeasures20cmby10cmby5cm.Iftheblockofgranitehasamassof2700g,whatisthedensityofthegranite?
Section7.3DescribingMatter
I.PropertiesofMatter
• Properties (orcharacteristics)areusedtodifferentiateonetypeofmatterfromanother.– PHYSICAL propertiescanbeobservedormeasuredandarebrokendownintotwogroups:qualitativeandquantitative.
• QUALITATIVE: propertiesthatcanbedescribedbutnotmeasurede.g.state,colour,malleability (poundintosheets),ductility (pullintowires),crystallinity,magnetism
• QUANTITATIVE: propertiesthatcanbemeasuredusingnumberse.g.solubility(dissolvesinwater),conductivity,viscosity,density,melting/freezingpoint,boiling/condensingpoint
• Mattercanbeorganizedindifferenttypes.
• APURESUBSTANCE isasubstancemadeupofonlyonekindofmatter.Ex.gold,water,andoxygen.
• Anelement isapuresubstancethatcannotbebrokendownorseparatedintosimplersubstances.
Ex.goldandoxygen.WaterisNOTanelementbecauseitcanbebrokendownintohydrogenandoxygen
• Acompound isapuresubstancecomposedofatleasttwoelementscombinedinaspecificway.
Ex.water.
• Amixture ismorethanonesubstancecombinedtogether
Either• Elementandelement• Elementandcompound• Compoundandcompound
Statewhetherthefollowingareanelement,acompound,amixtureoftwoelements,amixtureoftwocompounds,oramixtureofanelement
andacompoundA
B
C
D
E
F
G
H
I
II.Mattercanalsochange:
PhysicalChange• Thepropertieswillremainthesame (orcanreturntotheoriginal)
• Nonew substanceisproduced• Caneasilychange back• Examples:changeofstate,dissolving,mixing
ChemicalChange• Product(whatyouendwith)isdifferentfromthereactant(startingmatter)• Hardorimpossibletoreverse• Examples:newcolour,heatorlightgivenoff,bubbles