Preparation and analysis of inorganic and organic compounds Essay

Task 1 titration of sodium hydroxide with hydrochloric acid In this experiment the sodium hydroxide is neutralized with Hydrochloric acid to produce sodium chloride (the soluble salt) it is then crystallized in a dish. The equation for the above reaction is →NaOH(aq) + HCl(aq) → NaCl(aq) + H20(l) Method Add 25cm3 of sodium hydroxide into a conical flask then add couple of drops of methyl orange indicator Next fill the burette with HCL using a funnel to the 0 mark Add HCL to sodium hydroxide in small amounts swirling constantly keep adding until the solution changes to a red colour record your result Using the same volume of HCL now add it to another 25 cm3 of sodium hydroxide to produce a neutral solution Use a Bunsen burner and an evaporating dish to reduce the volume to half Finally leave to evaporate in a crystallizing dish to produce a white crystalline solid 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: Rough 1 2 Final burette reading 19.9 20.5 20.6 Initial Burette Reading 0.00 0.00 0.00 Titre 19.9 20.5 20.6 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