Ib Eggshell Report

Candidates name Eunika Orlowska Candidates subprogram Schools name Schools number Determining the sum of CaCO3 in casing of hens egg institution DCP CE feeling 1 Aspect 2 Aspect 3 institution The back titration is a manner employ in determining the descend of redundancy of the reagent. The calcium change is a agency which gives the plate stiffness. Research question What is the pith of calcium carbonate in the racing shell mea sealedd by back titration? instrument panel 1. Variables.Type of variable Variable Unit subordinate Amount of calcium carbonate in eggshell % by mint strong-minded Volume of measured excess of hydrochloric aced cm3 Controlled Volume of hydrochloric venomous charge of eggshell Temperature Amount of phenolophateine cm3 g oC drop Uncontrolled Purity of solutions biological diversity of eggs Pressure hPa Equipment burette 5 beakers 50 cm3 baguette 1 plastic pipette balance secure 2,5 g of eggshell mortar c cm3 of 1 groindm-3 hydrochloric demigod ap. 70 cm3 of 1moldm-3 sodium hydroxide 20 cm3 pipette Risk estimate you have to remember to wear gloves, gape and apron. Solutions may be irritating. Method rag to sparge eggshell in the mortar. satiate each of the 5 beakers with 20 cm3 of hydrochloric astringent measured by glass pipette. extend 0. 5 g of eggshell dust to each beaker, measured by balance. patch the replyion of eggshell with acid occurs, arrive at the buret and clamp for titration. Make sure they are clean. Pour NaOH solution into the buret to the 0 take aim. Make sure all of the eggshell reacted with the HCl. If non, you can help the reaction by exploitation the baguette.Put two drops of phenolophateine into each beaker using the plastic pipette. Take the first beaker and titrate the excess of hydrochloric acid. When the solution starts to be pinkish, land the volume of titrated NaOH. Refill the buret to the 0 level and repeat the procedure for each beaker. mobilize to record the matters. Remember to be certain and to leave your workplace clean information Collection defer 2. Raw data. The lean of eggshell reacting with HCl and titrated NaOH. Number of trial Weight of eggshell g0,01g Volume of HCl cm30,05cm3 Volume of titrated NaOH cm30,05cm3 1 0. 9 20. 00 9. 60 2 0. 50 20. 00 11. 50 3 0. 51 20. 00 11. 60 4 0. 50 20. 00 9. 90 5 0. 50 20. 00 10. 30 meanspirited 0. 500,01 20. 000,05 9. 930,05 Standard deviation 0. 00047 0. 00 0. 29 Uncertanties were taken as in measurments, not calculated by formula, to avoid in addition large and unreliable uncertainties in still calculations in which theyre calculated according to formulas in trip of division and multiplication =dA/A+dB/B, where d is boilers suit hesitation, dA is uncertainty of A and dB is uncertainty of B in case of addition and subtraction d=dA+dB, where where d is overall uncertainty, dA is uncertainty of A and dB is uncertainty of B Tria ls 2 and 3 were rejected because of similarly large differentiation of results. Data bear on Two reactions occured in the experiment. Firstly, the HCl reacted with CaCO3 and secondly, the excess of HCl was neutralize by NaOH. 2HCl + CaCO3 CaCl2 + CO2 + piddle HCl + NaOH NaCl + H2O 1. collusive the numerate of HCl at the root of reaction CmHCl = 1. 0 moldm-3 VHCl = 20. 00 cm3 = 0. 20 dm3 0. 00005 n = Cm * V n = 1. 0* 0. 020 = 0. 020 mol 0. 00025 2. Calculating mean count of NaOH which neutralized the excess of HCl CmNaOH = 1. 0 moldm-3 VNaOH = 9. 93 cm3 = 0. 0099 dm3 0. 00005 n = Cm * V n = 1. 0 * 0. 0099 = 0. 0099 mol 0. 0005 3. Calculating the summate of HCl which reacted with CaCO3 0. 020 mol 0. 0099dm3 = 0. 010 mol 0. 00075 4. Calculating the amount of CaCO3 which was in the eggshell We know that the grinder ratio in the reaction in the midst of HCl and CaCO3 is 2/1, which means that 2 moles of HCl react with 1 mole of CaCO3. If 0. 010 moles of HCl reacted with CaCO3 then in that respect was 0. 05 mole of CaCO3 in the eggshell. nCaCO3 = 0. 010/2 = 0. 0050. 0075 5. Calculating the contri barelyion of CaCO3 in the eggshell. MCaCO3 = 40. 09 + 12. 01 + 3 * 16,00 = degree Celsius. 1 gmol-1 nCaCO3 = 0. 005 mol 0. 0075 m = M * n m = 0. 005* hundred. 1 = 0. 50 g 0. 0075 meggshell=0. 50 0. 01 CCaCO3 in eggshell = 0. 50 / 0. 50 = 100 % 3. 5% Table 3. The results and uncertaities Calculated value Value indecision Number of moles of HCl at the beginning of reaction 0. 020 mol 0. 00025 mol Mean amount of NaOH which neutralized HCl 0. 0099 mol 0. 005 mol Mean amount of HCl which reacted with CaCO3 in the eggshell 0. 010 mol 0. 00075 mol Number of moles of CaCO3 in the eggshell 0. 005 mol 0. 0075 mol Molar mass of CaCO3 100,1 gmol-1 Percentage of CaCO3 100% 3. 5% The eggshell consists of 94-97% of calcium carbonate, meanly 95. 5 %. From imperturbable data it is 100%, which suggests that circumstances flaw was not big and remains in accepted value of 20%. percentage geological fault = (theoretical value observational value ? theoretical value) x 100% = (95. 5 100 ? 95. 5) = 4 %decisiveness and Evaluation The eggshell consists of 94 97% of calcium carbonate. The experiment suggests that the eggshell has 100% of calcium carbonate and the percentage error is 4 % which means calculations and results where accurate. The fact that the result has shown 100% of calcium carbonate in the eggshell may lay in the construction of eggshell which is biological utensil to give hens embryo the beaver practicable environment for development. Apart from calcium carbonate, there are other components of eggshell, for typeface milligram carbonate and calcium phosphate which to a fault react with hydrochloric acid.Reaction of calcium phosphate with hydrochloric acid Ca3(PO4)2 + 6HCl 3CaCl2 + 2H3PO4 this reaction shouldt have influence on titration that much, because as a result theres the equal number of hydr ogen ions which can be neutralized, but the second reaction, of magnesium carbonate and hydrochloric acid MgCO3 + 2HCl MgCl2 + CO2 + H2O similarly takes HCl to its reaction, decreases number of H+ ions and so suggests that more HCl reacted with calcium carbonate. This is the uncontrolled variable, the impurity of the eggshell, which alter the result.Other factor, which may have had influence on the results is the humans imprecision. The used equipment was as accurate as possible in trail laboratory, but still, the titration is make by hand and by eye, which may make mistakes although back titration is the best possible flair in school laboratory to check the amount of special(a) components in mixtures. Other method, which would distinguish between magnesium carbonate and calcium carbonate is gas spectrometry mass spectrometry. This method uses combined gas chromatography and mass spectrometry. First, the amount is put into gas chromatograph.The mobile phase, in which the pa rticles of substances move towards the stationary phase is made of unreactive gas, such as north or helium. In this, the substance is unaffectionate into particular components and then, the mass spectrometer analyses the components to see them. This method is commonly used to set the ingredients of substances, of food, beverages, perfumes. Also, it is useful in medicine and and in exploring Universe, for example, one GC-MS was taken by marvel to examine the surface of Mars. Summing up in school laboratory, accuracy of experiments is limited by equipment.Better accuracy can be obtained by using more accurate balance, as no other equipment can be changed in used method. Back titration cant be replaced by other methods of determining the percentage of CaCO3 in the eggshell, as it is the best way to do it in school laboratory, although largely more accurate methods are created, using machines which exclude the human factor from experiments, for example gas chromatography mass spe ctrometry. Bibliography http//antoine. frostburg. edu/chem/senese/101/consumer/faq/eggshell-composition. shtml eighteenth November 2012 J. Green, S. Damji Chemistry IBID 2008