Why do we have them?

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.