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Laboratory Equipment - Use of Equipment

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Laboratory Equipment - Use of Equipment

  1. 1. Laboratory Equipment Use of equipment 1
  2. 2. Safety gogglesUsed to protect youreyes when heatinganything or mixingchemicals.Protects eyes frombrokenglass, chemicals, andflames. 2
  3. 3. Safety showerUsed for chemical oracid spills or in caseof fire.Eye wash stationused when chemicalget into eyes. 3
  4. 4. Beaker/Beaker tongsMost versatileglassware-heatingchemicals onhotplate, mixingsubstances, etc.Volume graduationsshould be used onlyfor "ballpark"estimates. 4
  5. 5. Crucibles/Crucible tongsUsed to hold smallamounts of chemicalsduring heating at hightemperatures, especially if you want tokeep oxygen out ofthe reaction (just puton the cover).Used for picking upcrucibles and cruciblecovers only. 5
  6. 6. DessicatorsProvide a dry environment for acrucible or a given substanceto cool down, since moisturecan affect mass results.– Common dessicant-anhydrous calcium chloride.Colored indicator crystals areusually included to tellcondition of dessicant.– Gray color in crystals-dessicant is dry and will absorb moisture.– Pink color-dessicant is "hydrated". When this happens, the water can be removed by heating it in an oven. 6
  7. 7. Dropping bottleStore and disperse avariety of liquids. 7
  8. 8. Drying ovenUsed to dry materialsfaster. 8
  9. 9. Erlenmeyer flaskShape constructed tofacilitate swirling ormixing of reactants.NOT precise-250 mLflask typically holds270 mL or so.Use only forapproximatemeasurements. 9
  10. 10. Evaporating dishUsed to recoverdissolved solids byevaporation.While it can beheated, it should notbe used for "strong"heating. 10
  11. 11. Florence flaskRounded bottommakes it ideal forboiling liquids.It also makes thisflask easy to tip overwhen sitting on thelab table. 11
  12. 12. ForcepsUsed to grasp/holdsmall items.Often used fordissection.Not called tweezers. 12
  13. 13. Fume Hood:Safety glass-frontcabinet w/exhaustfan.It is used forexperiments known toproduce noxiousfumes or smoke. 13
  14. 14. Do the following to perform an experiment in thehood:– Raise the door of the hood– Turn on the light and set up the apparatus– When all material for the experiment is ready, turn on the fan– Pull the hood door at least 1/3 way down– Perform the experiment– When finished, pull the door all the way down until all smoke and fumes are removed– Turn off the fan and light, then remove the equipment to a regular lab station for cleaning– Leave the hood clean 14
  15. 15. Long stem funnel (filter funnel)When lined with filterpaper, used to filtersuspended solidsfrom a liquid.Aides in pouringliquids into smallopenings. 15
  16. 16. Glass stirring rod w/rubber policemanTool to mix reactants.Pour liquid down along itto keep it from splashingout.Movement of the rodadditionally helps tospread the heat evenly.Rubber policeman keepsglass rod from scratchingglass beaker or othercontainer. 16
  17. 17. Graduate cylindersMake accuratemeasurements of liquidvolumes.Bumper ring on largercylinders is to preventbreakage if tipped over.Keep it near the top. 17
  18. 18. Graduated pipetsCan have bulb or pipet pump.Convenient way to accuratelytransfer a small volume ofliquid. – Volumetric pipet-used to measure one amount only. – Graduated pipet-lot of lines so you can measure many different amounts.Before making an accuratetransfer, the user should pumpthe desired liquid into thepipet, roll the pipet horizontallyto coat the entire interiorsurface with the liquid, andthen allow the liquid to drainthrough the tip. 18
  19. 19. Micro flame burnerFueled by butane.Gives pure hot flamewithout smoke.Reach temperatureyou need faster. 19
  20. 20. Micro spatulaUsed to transfersolids. 20
  21. 21. Microscope slide/cover glassMicroscope slide withor without well.Cover slip or coverglass-flattens liquidsfor better high powerviewing, protects lensfrom liquids. 21
  22. 22. Mortar and pestleUsed to grind solidsinto powders. 22
  23. 23. Spot plateHas number of smallwells.Chemicals are placedin the small wells, andthe reaction can beobserved as it takesplace in the well. 23
  24. 24. Support ringAttaches to thering stand and isused to supportglassware abovethe lab table. 24
  25. 25. Test tube/Test tube rack/Test tube holderTest tube-used ascontainer to holdchemicals duringheating or otherreactions.Test tube rack-supports testtubes, hang tubesupside down fordrying.Test tube holder-usedin cases of heating. 25
  26. 26. TongsUsed to hold or pickup many items, butwork best as tongs forpicking up hotevaporating dish. 26
  27. 27. Transfer pipetUsed to transfer verysmall amounts ofliquids. 27
  28. 28. TripodCan be placed overBunsenburner, alcohollamp, or micro flameburner.Use with wire gaugeor clay tripod. 28
  29. 29. Utility clampWhen attached to thering stand, this clampis used to hold a largetest tube or Florenceflask above the labtable. 29
  30. 30. Volumetric flasksUsed to prepare solutions of exactconcentrations of solutions.It has a precise graduation line in theneck of the flask.Never heat substances in them.First rinse inside with solvent, thentransfer a small amount of solventfollowed by the required amount ofsolute, and swirl.Further fill the flask with solvent tojust below the mark etched in theglass.Last few drops added with amedicine dropper or Pasteur pipet foraccuracy.Finally, w/stopper and basesupported, invert flask about tentimes to ensure homogeneity in themixing. 30
  31. 31. Watch glassUsed like evaporatingdish for drying verysmall amounts ofmaterial.Used to coverbeakers.Used for weighingsmall amounts ofmaterial. 31
  32. 32. Weighing paperUsed with a balanceso that chemicals areplaced on thepaper, instead ofdirectly on thebalance. 32
  33. 33. Wash bottlesIn the general chemistrylab, are usually filled withdistilled or deionizedwater.Used for rinsing solids outof a container whenfiltering.Used to rinse glassware. 33
  34. 34. Wire gauze/Clay triangleUsed as a support forcontainers whenplaced across asupport ring above aburner.Wire gauze spreadsout flame/heat evenlyover container.Clay triangle can holda funnel duringfiltering. 34
  35. 35. Measuring the volume of a liquid with a graduated cylinder: Surface of liquid in cylinder curves to form a meniscus. Meniscus of most liquids curves up sides of container (center lower than edges). – Mercury is one of very few exceptions - it curves down at the edges. Always read bottom of curve. 35
  36. 36. Using the smallest graduation, estimatebetween the two lines where the meniscusfalls.As the diameter of the cylinderincreases, the curve of the meniscusflattens out.Putting card/paper behind meniscusmakes it easier to read. 36
  37. 37. Measuring the volume of a liquid with a pipet: Pipets are much more accurate than graduated cylinders. Liquid must be drawn into the pipet. Gradually release the pressure of your squeeze on the bulb and allow the liquid to be drawn into the pipet. – Draw more liquid than needed, but do not allow the liquid to enter the bulb. 37
  38. 38. Measuring mass with an electronic balance:Never place a chemical directly on balance pan-use container.Place container on balance-its mass is displayed.Press Zero button-balance resets to zero andignores mass of container.Place substance to be weighed into container-balance will show only the mass of substance.When container is removed, pressZero button again. 38
  39. 39. Measuring mass with a triple- beam balance:Place object on balance pan.Move tares on beams to balance mass.Back beam graduated in 10 gram steps/middle beamgraduated in 100 gram steps.– Tares on these two beams are in the notch for the whole number of grams and not in between notches.The front beam is a sliding scale graduated in grams.The tare on this beam can be positioned anywhere onthe scale.Masses on a triple-beam balance canbe read to tenths of a gram, andestimated to hundredths. 39
  40. 40. Filtering a precipitate from a solution:Filtering a solid out of a liquid is done using filter paperand a filter funnel.The filter funnel is supported by the ring on a ring stand.Lay a clay triangle across the ring, then place the filterfunnel into the triangle.To prepare the filter paper, fold the paper in half, thenfold it in half again. 40
  41. 41. Catch three of the four edges of paper at open edge.– Squeeze sides of folded paper and cone will form w/3 thicknesses of paper on one side and one thickness of paper on the other.– Place this cone of paper into the filter funnel.Place catch dish under funnel.Wet down inside of filter paper with wash bottle-it sticksto funnel.Carefully pour liquid to be filtered into mouth of funnel.– Do not let the liquid rise to the top of the filter paper.– If any liquid goes over and around the paper, your procedure is ruined.– Be patient, it will take time for the liquid to move through the pores of the paper.When all original liquid has been poured into thefunnel, use wash bottle to rinse any remaining precipitateout of the original container.Do not touch or try to stir the liquid inside the filter paper.– The wet paper is easily torn, which will ruin your procedure. 41

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