8th grade review outline key.docx

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1、8thGradeReviewOutlineChapter11.Explain“mass”,“volume”,“density”,“weight”,and“inertia”.Mass:(unit:kg)theamountofsubstanceinanobjectVolumeistheamountofspaceanobjecttakesup.VolumealsomeanshowmuchsomethingholdsDensityisdefinedasmassperunitvolume.Itisameasureofho

2、wtightlypackedandhowheavythemoleculesareinanobject.Densityistheamountofmatterwithinacertainvolume.(unit:kg/m3)Weight(unit:N):gravitationalpullonanobjectInertia:allobjectsresistattemptstomakethemgofaster,slower,orinadifferentdirection.•Masslarger,inertialarge

3、r.2.Expresstheunitprefixeswiththepoweroften.3.Density=mass/volume(conversionofdensityunits)4.Relativedensity=densityofsubstance/densityofwater(specificgravity)Examplecalculationquestions11=___2.5×10-2________dmg/m3=____1.20×10-3_____kg/cm31702x1010mW=___1.70

4、2×101_______GW124x108mm2=___1.24×106_________dm211Thedensityofair1300g/m3.Whatisitsrelativedensity?1.3×10-3Findthemassof600mLair.Whatistheweightoftheairoftheearth?7.644×10-3NNote:WeightofobjectonEarth=mass×9.8massshouldbeintheunitofKgNOTg.Theweightofanobject

5、is42140N,anditsdensityis21.5g/mL.FinditsvolumeinL.Step1.MassoftheobjectisW=m*9.842140/9.8=4300kgStep2.m/V=DD=21.5g/mL=21.5g/cm3=21.5*103kg/m3=4300kg/VV=200LThemassofacylinderis251.2ganditsdensityis2000kg/m3.Iftheradiusis2cm,whatistheheightofthecylinder?D=200

6、0kg/m3=2g/cm3=h=10cmTherelativedensityoftheearthis5.52.Whatisthedensityinkg/m3?5.52×103kg/m3Thereissomewaterinameasuringcylinder.IfobjectAisputintothecylinder,thewatersurfacerisesto60mL.IfobjectBisputintothecylinder,thewatersurfacerisesto80mL.TheratioofA’sde

7、nsitytoB’sdensityis5:2,andtheratioofA’smasstoB’smassis5:6.Howmuchwateristhereinthecylinder?Assumexmlofwaterinthemeasuringcylinder.11VolumeofA:60mL-xVolumeofB:80mL-xx=50mL11Chapter51.MovingParticles1)Whatiskinetictheory?Allmatterismadeoftinyparticles•Theparti

8、clesarealwaysmoving(theyhavekineticenergy)•Thehigherthetemperature,thefastertheparticlesmove•Particlesattracteachotherstronglywhenclose.•Thedifferencesbetweensolids,liquids&gasescanbeexplainedwi