Unit 2B - Assignment unit 2B PDF

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Assignment unit 2B...

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Unit 2 Experiment 1 : Calibration of a digital and liquid thermometer Aim: to calibrate a digital thermometer and a liquid thermometer effectively Equipment • Two beakers • Digital thermometer • Liquid thermometer • Stopwatch • Kettle • Pen and paper • Ice • Water Method 1. Get hold of two beakers and label them beaker A and beaker B 2. Place ice in beaker A 3. Put a digital thermometer and a liquid thermometer in the beaker with the ice 4. Using a stopwatch time it for one minute 5. Record the readings for both thermometers 6. Leave both thermometer at room temperature for around 5 minutes 7. Boil some water using a kettle 8. Pour the boiling water in beaker B 9. Place both the digital thermometer and the liquid thermometer in beaker B 10. Time it for 1 minute and Record the readings Risk Assessment

If substances are spilled they can cause falls and trips

Brush/ wipe away any spillages before continuing with the experiment If any glass equipment is Carefully brush away broken is could cause any broken glass and in severe cuts or harm the case of cuts seek skin medical attention Boiling water can cause Make sure any spilled severe burns to the skin boiling water is carefully or eyes handles and in case of burns seek medical attention

Avoid walking close to the affected areas before its fully cleared up. Handle all glass equipment with care and attention Wear heat protective gloves and appropriate clothing, handle the kettle with care

Results

With Ice With Boiling Water

Digital thermometer temperature ‘C 0.5 82.8

Liquid thermometer temperature’C 6 83

Conclusion Overall the experiment was done making sure that the minimum risk of error was conducted. However could have been some extra steps we could have taken aim order to make the final results more reliable. First of all I think the thermometer should not have been placed in the beaker it self but held in the ice or boiling water so that they don’t touch the surfaces around them. This is because the glass of the beaker could have caused anomalies in the results due to its own temperature stability. Moreover in the method it wasn’t specified what type of ice had to be used to in order to make sure the results are as reliable as possible I would say it’s important to make sure that the ice being used for this very experiment is crushed ice and not cubes. This is because cubes of ice tend to cause higher temperature readings. Another way that this experiment could have been conducted better was to fill the beaker with cold water to at least half way and clearly make sure that the ice was touching the bottom of the beaker and not floating. To make sure the ice does t float in the beaker we have to make sure we added the right amount of cold water otherwise freezing point will not be achieved. Another way to make sure the experiment was done with the minimum percentage error is to calibrate all the other equipment before use. To start the percentage error for the stopwatch would be-+0.1 seconds therefore it’s really important it’s calibrated before

hand. Also one way we know that the experiment doesn’t give us 100% accurate results it’s because the percentage error for the thermometer is +0.5’C. Lastly the percentage error for the beaker is -+1ml so to reduce all these uncertainties it’s important all equipment is carefully calibrated and all steps are done with concentration. Overall I think the results are acceptable. Experiment 2: Freezing points of stearic acid and paraffin wax Aim: to successfully indentify freezing points of steric acid and paraffin wax using a digital and liquid thermometer and calculate the rate of reaction. Equipment • Wooden clamp • Wooden clasp • Water bath at 50’C • 2 test tubes • Praraffin wax • Stearic acid • Stopwatch • Digital thermometer • Liquid thermometer Method: 1. First the wooden clasp should be attached to the wooden clamp 2. The stearic acid which should be in a test tube within the water bath at 3. 50’C should be removed at the same time as adding the digital and liquid thermometer 4. The test tube should be attached to the wooden clasp 5. A stopwatch should immediately be started to time when the acid 6. freezes and for following 40 minutes 7. The temperature at 0 minute should be recorded 8. Every minute the temperature of the acid should be recorded in an appropriate results table

9. Create a graph for the results collected 10. Repeat this method using for paraffin wax by just changing the acid to the wax Risk assessment Stearic acid can cause skin irritation and nausea/ vomiting if ingested Paraffin wax can cause severe burns/ irritation and contact with eyes can be harmful If substances are spilled they can cause falls and trips

In case of contact with skin/eyes or ingested wash thoughtfully with water for 15 minutes In case of burns seek medial attention and in case of irritation wash with water thoughtfully Brush/ wipe away any spillages before continuing with the experiment If any glass equipment is Carefully brush away broken is could cause any broken glass and in severe cuts or harm the case of cuts seek skin medical attention

Results: Steric Acid Time 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Digital thermometer 69.2 67.2 62.2 58.3 55.4 54.8 54.6 54.3 54.1 53.8 53.2 52.6 52.1 51.6 51.1 50.6 50.1

Liquid thermometer 67 62 59 56 55 54 54 53 53 53 53 53 53 53 53 53 52

Keep the acid away from mouth. Wear appropriate clothing and googles Wear appropriate clothing and goggles at all times Avoid walking close to the affected areas before its fully cleared up. Handle all glass equipment with care and attention

17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

49.3 48.6 48.1 47.3 46.8 46.2 45.5 44.8 44.2 43.1 43.2 42.1 42.1 41.4 40.6 39.8 39.1 39.5 38.4 37.8 37.1 36.1 35.1 34.3

52 52 51 51 51 50 50 49 49 48 47 47 46 46 45 44 43 42 40 40 39 38 37 36

STERIC ACID FROZE AT 6 MINUTES Paraffin Wax Time 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Digital thermometer 36.1 65.5 61 59.1 58.1 58.8 58.4 58 57.5 57 56.5 56.1 55.4 54.8 54.1

Liquid thermometer 39 61 59 58 57 57 57 57 56 56 55 55 55 54 53

15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

53.3 52.3 51.4 50.4 49.2 47.7 46.7 45.6 44.5 43.2 42.5 41.4 40.6 37.7 38.8 37.8 37.2 36.5 35.8 35.1 34.3 33.7 33.1 32.6 32.1 31.5

PARAFFIN WAX FROZE AT 27 MINUTES

53 52 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 36 36 35 34 34 33 32

T1) 62.2 – 55.4 = 6.80 4–2=2 6.8 /2 = 3.4 T2) 52.1 – 50.1 = 2 16 – 12 = 4 2/4 = 0.5 T3) 38.4 – 36.1 = 2.3 38 – 35 = 3 2.3/3 = 0.8 Total 3.4+ 0.5+0.8=4.7 4.7 : 3 = 1.56

T1) 59 – 48 = 11 5-2=3 11/3=3.6 T2) 56-48=8 26-22=4 8/4=2 T3)40-38=2 38-35=3 2/3=0.6 Total 3.6+2+0.6=6.2 6.2/3=2.06

T1) 61.0 – 58.1= 2.9 4-2=2 2.9/2=1.45 T2) 54.1- 52.3=1.8 16-14=2 1.8/2=0.9 T3) 34.3-32.1=2.2 39-35=4 2.2/4= 0.55 Total 1.45+0.9+0.55=2.9 2.9/3=0.96

T1) 59-57=2 4-2=2 2/2=1 T2) 54-52=2 16-13= 3 2/3=0.6 T3) 36-34=2 37-34=3 2/3=0.6 Total 1+0.6+0.6=2.2 2.2/3=0.73

Conclusion: Steric Acid is identified as a fatty acid which are considered to be long hydrocarbons chains containing a carboxyl group at one end and a methyl group at the other. With the chemical formula of C18H36O2.

Stearic acid has a boiling point of 361’C and a melting point o f 69.3’C. Paraffin Wax is mixture of high molecular weight alkenes with the boiling point of 370’C and the melting point of 50-57’C. Paraffin wax is a stable compound up to 250’C therefore pressure loss is low due to its low viscosity. The chemical formula for paraffin wax is CnH2n+2

Website: ChemWiki (2021) Steric Acid and sodium stearate https://www.ch.ic.ac.uk/rzepa/mim/domestic/html/stearic_acid.htm Website: MindTouch (2021) Wax https://chem.libretexts.org/Bookshelves/Biological_Chemistry/Supplemental_ Modules_(Biological_Chemistry)/Lipids/Non-glyceride_Lipids/Wax Website: Caymanchem (2018) Safety Data Sheet Steric Acid https://www.caymanchem.com/msdss/10011298m.pdf Website: Jmloveridge ( 2014) Safety Data Sheet Paraffin Wax https://jmloveridge.com/wp-content/uploads/2018/06/Paraffin-Wax-Version05.pdf...