RESULTS
My results for the experiment:
Average Volume = 26.35
Mass of Evaporating dish = 53.86 (Mass = 55.04 – 53.86 = 1.18g)
Mass = n x Mr = 0.025 x 58.5 = 1.4625
Calculating Percentage Yield 1.18 x 100 = 80.7 %
1.4625
Test for ions present
Sodium Na+ -- test carried out = flame test – result golden yellow
This happens as the electrons move to higher energy level and then fall back down when heated which gives out yellow light.
Chloride test → test carried out = add silver nitrate – result white precipitate of silver chloride was formed
Task (e)
Purity analysis of NaCl
In this task I will be showing the purity analysis of NaCl the same procedure will be carried out as before but this time 0.1 moldm-3 of sodium chloride is titrated with 0.05 moldm-3 silver nitrate the indicator will be the chromate indicator
The chemical formula for the following reaction is:NaCl(aq) + AgNO3(aq) → AgCl(s) + NaNo3(aq)
RESULTS
These are the results obtained for the following experiment:
Average Volume = 20.55
Converted to dm3 /1000
1)calculate no of moles of silver nitrate
N= C x V =0.05 x 0.02055 = 0.010275 moles
2)answer = no of mole of NaCl (1 : 1 ratio)
3) Calculate the actual concentration of NaCl
C= n/V = 0.010275 = 0.10275moldm-3
0.01
4)percentage purity
ppurity = 0.1 x 100 = 97.3%)
0.010275
Task 2
Method:
1)shake 2g of 2- hydroxybenzoic acid with 4 cm3 of ethanoic anhydride in a 100cm3 conical flask
2) add five drops of concentrated sulphuric acid agitating the flask for about 10 mins the whole wil form a crystalline mush
3) Dilute by stirring it in 4cm3 of cold glacial ethanoic acid and cool by placing in a water bath containing crushed ice
4) filter off the crystals using a Hirsch funnel and wash once with ice cold water
5) place the crude aspirin in a 100cm3 beaker add hot water not boiling water till it dissolves
6)cool and filter of crystals this process is known as recrystallisation
7) Take 4 test tubes add 2cm3 of distilled water in each and in 1 tube add one crystal of the product before recrystallisation and shake
8) Second tube add one crystal of the recrystallised product and shake
9) Third tube add one crystal of 2-hydroxybenzoic acid and shake
10) In last tube add one crystal of known pure aspirin and shake
11)To each tube add 2 drops in turn of neutral iron (III) chloride and shake
Following this method I got the following results
Mass at start was 2.04
Finishing mass was 2.08
Amount of yield:
138 →180
1 →180/138
1 →1.3
2.04 → 2.652
2.08 x 100 = 78.4%
2.652
Organic testing
To test for a phenol group
Method:
Add neutral iron III chloride(if a phenol group is present it will change into purple complex and if theres no purple then the aspirin is pure)
Using the following method my result showed a purple complex showing that my aspirin was impure
Melting point analysis
2 – hydroxybenzoic acid pure aspirin my sample
150 130 – 140 125
125/135 = 92.6%
