Topic: Lab Measurement and Introduction to Apparatus Notes

O level Chemistry Topic: Lab Measurement and Introduction to Apparatus Notes 1 Time Measurement Measured with the help of stopwatch Units: Sec, Min, Hours. Mass Measurement In chemical reactions mass increases and decreases. E.g. if gas is produced then mass decreases. Units: g, mg, kg. Apparatus: electronic digital balance Temperature Measurement 이 In Exothermic reactions heat is absorbed In Endothermic reactions heat is absorbed Unit: Farenheit/Celcius/ Kalvin Apparatus: Thermometer Apparatus: 1. Beaker 500 400 300 500ml 200 100 It is used for rough measurement of liquid. During measurement of liquid, narrow is the column, better will be themeasurement. As in case of beaker, column is broader, that's why measurement is rough. Beaker is available in variable sizes 2 2. Measuring cylinder/Graduated cylinder 3. Boiling tube 이 It is a very accurate apparatus for the measurement of liquid, as in case of measuring cylinder, column is narrow and it is easy to measure accurately. Graduated cylinder is a prefered apparatus to measure liquid, as in graduated cylinder, even a five centimetre cube cylinder is available. It is a comparatively wider tube. It is basically an enlarged form of test tube. It is specifically used for boiling of a liquid of a shorter level. 3 4. Bunsen burner 5. Conical flask It is a burner with gas supply. It is used for heating purposes. It has a supply of natural gas which burns in the presence of oxygen. It has 2-3 holes, through which air can enter and natural gas can burn completely. One of the titration partner is taken in the conical flask. The partner which is taken in conical flask is taken with the help of pipette. After addition of titration flask partner, indicator is added with the help of dropper. 4 6. Pipette 7. Burette • 이 It is a long narrow apparatus, which has a bulb in the centre of it. It has only one mark above the bulb, this type of pipette can only measure one volume. There is another type of pipette, which has many measurement marks, it is called graduated pipette. 이 It is an apparatus with a controlling tap at the end. Its stop reading is 0, when it is completely filled and no volume is taken out. When liquid is taken out of the burette, e.g the burette reading is 8.7, volume used is out of the burette is equal to (final reading) - (initial reading). Volume used=8.7-0.0=8.7 centimeter cube. 5 8. Test tube 9. Test tube holder 10. Test tube rack It is a small sized open mouth apparatus, used for the performance of experiments at a smaller scale. It is mostly used for the performance of test for the identification of gases and ions. It is a metallic apparatus, with a wooden handle, used for holding test tubes and boiling tubes. isco 6 It is an apparatus which is used to keep the test tubes, while performing experiments and to keep in the cupboards. 11. Tripod Stand 12. Wire gauze It is a three legged metallic apparatus, which is used for heating and for filtration. . It is a criss-cross of iron wires, having ceramic coating in the centre, it is used to give the base to the apparatus, which is heated on the tripod stand. 7 13. Crucible 14. Gas jar It is a small apparatus, which has a lid on it. When the lid is tightly closed, it is done so that reactants do notescape. When the lid is loosely closed, it is done so that oxygen can enter to react with the reactants. It is an apparatus which is used to collect the gas 15. Rubber pipette filler/ /Safety bulbs It is used to fill the liquid in the pipette. A vacuum is created, and liquid starts travelling up in the pipette. It student will do it without this apparatus, chemicals can go into the mouth of the student. 8 16. Pestle and Mortar Pestle 이 It is used for crushing and grinding. Mortar 17. Lab thermometer 36 38 40 42 35 37 39 41 18. Funnel It is an apparatus which is used to measure the temperature ofa reaction. It is also called filter funnel. It is used to shift large volumes to narrow apparatuses. It is also used to filter a solid and a liquid from each other, by using a filter paper. 9 19. Gas syringe 20. Spatula It is used to measure volume of a gas. Units are centimetre cube. It is used to take solid from a reagent bottle for a reaction. 21. Volumetric flask/ Graduated flask/ Measuring flask 이 이 It is along narrow neck flask with a short bottom. It is the most accurate apparatus for volume measurement.It is available in variable sizes. 10 22. Centrifugation machine reret 23. Centrifugation tube . It is used to sum up the very fine, separated particles. These are small sized tubes in which liquid and very fine particles are taken. These are placed in centrifugation machine. 11 24. China dish/ Evaporating dish 25. Tongs It is an open container which is used for heating andevaporating. 12 It is a scissors like apparatus which is used to hold an apparatus. 26. Dropper 13 It is used to take 2-3 drops of a liquid. Titration In titration, one of the partner is taken in the burette where as the other partner is taken in the conical flask. The partner taken in the conical flask is taken by the pipette. Indicator is a chemical/reagent which is added in the conical flask along with the conical flask partner. Indicator is always in 2/3 drop amounts. It is taken with the help of dropper. Indicator tells about chemical reaction happening in titration. Euret crota.nirg tas cac) Stop-oock Aad or La and ndcat 14 Pipette Difference between crucible and china dish A crucible is an apparatus that has a lid on it. If the lid is tightly fitted, it means that we don't want the reactants to go out of the crucible. If the lid is loosely fitted, it is to allow oxygen to enter the crucible and to react with the reactants. Crucible is basically used for the performance of chemical reactions on a smaller level. A china dish is an apparatus that is used for evaporation of a liquid to obtain a dry solid Pestle and Mortar . These are used for crushing and grinding solid substance into powder, as powder gives a quicker reaction. 15 Burette Reading . • 0 . The purpose of burette reading is to see how much volume of liquid has been used. It uses two terms namely, final reading and initial reading. Initial reading is the reading of the burette before the liquid has been used. Final reading is the reading of the burette after the liquid has been used. Initial reading is subtracted from the final reading, to see how much volume of liquid had been used. Initial reading - final reading. Burette data is collecting the burette reading for all the titrations done. The ones showing the highest volume of liquid used up will be added and then they will be divided by their total quantity. Three titrations were done. Parts of the burette with liquid levels before and after each titration are shown below 1ot btrator 24 ndraoo -25 18 2 -2 -26 (d) Usethe dragram to complete the following results table Titration number Final burette reading cm 1 Final burette reading cm Volume of 0 100 mol dm☐3 sodıum hydroxıde cm Best tutration results (✓) -4 _5 3rd titrabon -21 -28 -20 Summary Tick the best titration results U'sing these results, the average volume of 0.100 mol dm sodıum hydroxde was cm³ (4]