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Why do we have them?. When we measure things, we want to measure to the place we are sure of and guess one more space. So, they show the uncertainty in our measurements. - PowerPoint PPT Presentation
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Why do we have them?Why do we have them?
When we measure things, we want to measure to the place we are sure of and guess one more space.
So, they show the So, they show the uncertaintyuncertainty in in our measurementsour measurements
Since the marks on this Since the marks on this ruler are subdivided as ruler are subdivided as they are, our answer for they are, our answer for the length of this nail has the length of this nail has
33 significant figures. significant figures.
However, we only However, we only have significant figures have significant figures
when we are when we are measuringmeasuring something. something. CountingCounting will give you will give you
an exact number.an exact number.
Lab EquipmentLab Equipment
BeakerBeaker Holds chemicalsHolds chemicals
during mixing, during mixing, heating, and heating, and storagestorage
Acts like a bowlActs like a bowl InaccurateInaccurate
measuring devicemeasuring device
Erlenmeyer FlaskErlenmeyer Flask Holds chemicalsHolds chemicals
during mixing, during mixing, heating, and heating, and storagestorage
Acts like a bowlActs like a bowl InaccurateInaccurate
measuring devicemeasuring device
Volumetric FlaskVolumetric Flask Holds chemicalsHolds chemicals
during mixing and during mixing and storagestorage
Accurate Accurate measurement of a measurement of a specific volumespecific volume
FunnelFunnel Aids in pouring and Aids in pouring and
filtering processfiltering process
Watch GlassWatch Glass Acts as a cover Acts as a cover
during heating and during heating and storagestorage
Looks like a giant Looks like a giant contact lencontact len
Evaporating DishEvaporating Dish Container used to Container used to
allow materials to allow materials to evaporateevaporate
Crucible and CoverCrucible and Cover Used to hold Used to hold
materials that need materials that need to be heated to to be heated to higher higher temperaturestemperatures
Crucible TongsCrucible Tongs Used to hold Used to hold
heated cruciblesheated crucibles
Bunsen BurnerBunsen Burner Used to heat Used to heat
materialsmaterials
StrikerStriker Used to light Used to light
burnersburners
BalanceBalance Used to determine Used to determine
the mass of the mass of materialsmaterials
Graduated CylinderGraduated Cylinder Used to measure Used to measure
liquids accuratelyliquids accurately Must look at Must look at
meniscus of the meniscus of the liquid when taking liquid when taking readings readings
Iron RingIron Ring Attaches to ring Attaches to ring
standstand Holds various Holds various
equipment while equipment while they are heated they are heated
Buret ClampBuret Clamp Attaches to ring Attaches to ring
standstand Holds burets during Holds burets during
titrations titrations
Utility ClampUtility Clamp Attaches to ring Attaches to ring
standstand Holds various thin Holds various thin
equipment while equipment while they are heated they are heated
GogglesGoggles Protect eyes during Protect eyes during
experimentsexperiments
Ring StandRing Stand Used to support Used to support
devices during devices during laboratory laboratory proceduresprocedures
BuretBuret Used to accurately Used to accurately
and slowly add and slowly add liquidsliquids
Used most often in Used most often in titration titration experimentsexperiments
ThermometerThermometer Used to measure Used to measure
the temperature of the temperature of various materialsvarious materials
Gas-collecting tubeGas-collecting tube Tube used to Tube used to
collect gases.collect gases. Usually used in the Usually used in the
inverted positioninverted position
Test TubeTest Tube Used to hold small Used to hold small
samples during samples during heating and heating and storagestorage
Test Tube RackTest Tube Rack Used to hold Used to hold
multiple test tubesmultiple test tubes
Test Tube HolderTest Tube Holder Used to hold one Used to hold one
test tube, usually test tube, usually during heating or during heating or transporting test transporting test tubetube
ForcepsForceps Used to pick up Used to pick up
and separate small and separate small solidssolids
SpatulaSpatula Used to scoop Used to scoop
small quantities of small quantities of solidssolids
Can be used to Can be used to scrape the inside of scrape the inside of various equipmentvarious equipment
Mortar and PestleMortar and Pestle Used to crush and Used to crush and
grind materialsgrind materials
PipetPipet Used to dispense Used to dispense
small quantities of small quantities of liquidsliquids
StoppersStoppers Come in various Come in various
sizessizes Used to block Used to block
openings of various openings of various equipmentequipment
So, let us practice with So, let us practice with reading different pieces of reading different pieces of
equipmentequipment
Answer to WorksheetsAnswer to Worksheets ScalesScales
1)1) 622.89 g622.89 g2)2) 153.70 g153.70 g3)3) 200.54 g200.54 g4)4) 128.192 g128.192 g5)5) 205.548 g205.548 g6)6) 90.900 g90.900 g
Answer to WorksheetsAnswer to Worksheets Liquid VolumeLiquid Volume
a)a) 56.0 mL56.0 mLb)b) 4.35 mL4.35 mLc)c) 23.7 mL23.7 mLd)d) 16.8 mL16.8 mLe)e) 76.0 mL76.0 mLf)f) 5.3 mL5.3 mLg)g) 32.0 mL32.0 mLh)h) 3.5 mL3.5 mLi)i) 47.0 mL47.0 mL
ThermometersThermometersa)a) 68.0 68.0 b)b) -2.8 -2.8 c)c) 11.0 11.0 d)d) -1.1 -1.1 e)e) 28.1 28.1 f)f) 16.0 16.0 g)g) 8.0 8.0 h)h) -11.5 -11.5 i)i) 98.7 98.7
Instruments around the roomInstruments around the room BeakerBeaker BuretBuret Volumetric FlaskVolumetric Flask Graduated cylinderGraduated cylinder ScaleScale Erlenmeyer FlaskErlenmeyer Flask ThermometerThermometer
HomeworkHomework Look through your textbook. Find 10 Look through your textbook. Find 10
pictures that show a piece of pictures that show a piece of chemical equipment being used. chemical equipment being used. Name the page, the piece of Name the page, the piece of equipment and describe how it is equipment and describe how it is being used.being used.