sec 3 chem

UnitsandmeasurementsPhysical quantities Apparatus AccuracyTemperature Thermometer 1 decimal placeUpto0.5degreeCelsius(E.g.37.0<totheaccuracyof oned.p.>) Mass ElectronicBalance 2decimal placeUpto0.01g(e.g.2.56tomeasuremass) Time Stopwatch Nearest Second ● Volume( liquid)➔ Measuringcylinder ( nodecimal place, approximatelynearest cm³ )➔ Pipette( 25.0cm³, 1 decimal placealways“ 0“, volumemeasuredinmultiplesof 5)➔ Burette( 2decimal place, 2nddecimal iseither “ 0“ or “ 5“ )● Volume( gas)➔ Gassyringe( dependsonthegassyringe) ● Gascollection Method Experimental set up Characteristicsof gascollected Downwarddelivery ● Gascollectedismoredensethanair ( hencethegaswill sinksolubleinwater ) Upwarddelivery ● Gascollectedislessdensethanair ( hencethegaswill floatsolubleinwater ) ©wzkai

Displacement of water ● Gascollectedisinsolubleinwater Gassyringe ● It issuitabletocollect andmeasurethevolumeof anytypeof gas KineticParticleTheory 1. (a) All matter ismadeupof tinydiscreteparticles(b) Theparticlesarealwaysinconstant randommotion 2. Stateof matter Solid Liquid GasesArrangement ofparticles Verycloselypackedinanorderlymanner Closelypackedbut not inanorderlymanner Veryfar apart andinrandomarrangement Movement ofparticles Vibrateabout infixedposition Slideover eachother Movefreelyathighspeed Attractiveforcesbetweenparticles Verystrong Strong Veryweakoralmost negligible ©wzkai

Diagrams * 4rowsx4columns* similar sizes * shouldnot haveanypattern* shouldtoucheachother* shouldnot befloatingintheair(touchingtheground) * veryfar apart* at least 6particles 3. Changesof State Examplesof sublimeare● Mothballs● Dryice( solidCO2)● Iodine ©wzkai

● Ammoniumchloride( whitesolid) 4. Determiningthestateof matter 5. Heatingandcoolingcurve MELTING CONDENSATION ATheparticlesareverycloselypackedinanorderlymanner andvibrateat their fixedposition.(Solidstate) ATheparticlesarerandomlyarrangedandmovefreelyat highspeed. (gaseousstate) A-BAsthesolidisheated, theparticlesgainkineticenergyandstart tovibratefaster. A-BAsthegasiscooled, theparticleslosekineticenergyandstart tomoveslower. B-CAmixtureof solidandliquidexistshere. Duringthemeltingprocess, thetemperatureof thesubstanceremainsconstant. All theheatenergy takeninbytheparticlesisusedto B-CAmixtureof gasandliquidexistshere. Theparticleslosekineticenergyandtheymoveslower andcloser together. ©wzkai

overcometheforcesof attraction. betweenparticles. C-DTheparticlesarerandomlyarrangedandslide over oneanother. Thesubstancebecomes liquid. C– DTheparticlesbecomecloser, randomlyarrangedandslideover oneanother. Thesubstancebecomesliquid. BOILING FREEZING CTheparticlesarecloselypackedbut not inanorderlymanner andslideover oneanother. (liquidstate) CTheparticlesarerandomlyarrangedandslide over oneanother. (liquidstate) C-DAstheliquidisheated, theparticlesgainkineticenergyandstart tovibrate/ movefaster. C– DAstheliquidiscooled, theparticleslosekinetic energyandstart toslideover oneanother slower. D-EAmixtureof liquidandgasexistshere. Duringtheboilingp