Ib Eggshell Report

Candidates name Eunika Orlowska Candidates number Schools name Schools number determine the amount of CaCO3 in testiclehell of hens egg Design DCP CE position 1 Aspect 2 Aspect 3 Introduction The certify titration is a method used in determining the amount of unornamented of the reagent. The atomic number 20 carbonate is a substance which gives the plate stiffness. Research pass What is the amount of atomic number 20 carbonate in the racing shell measured by back titration? Table 1. Variables.Type of variable Variable Unit Dependent totality of calcium carbonate in plate % by people autonomous Volume of titrated excess of hydrochloric aced cm3 Controlled Volume of hydrochloric acid Weight of case Temperature kernel of phenolophateine cm3 g oC drop Uncontrolled Purity of solutions Biological diversity of eggs Pressure hPa Equipment buret 5 beakers 50 cm3 baguette 1 bulwarkdable pipette balance fix 2,5 g of eggshell mortar hundred cm3 of 1bulwarkdm-3 hydrochloric acid ap. 70 cm3 of 1moldm-3 sodium hydroxide 20 cm3 pipette assay assessment you have to remember to wear gloves, goggles and apron. Solutions may be irritating. Method Crush to dust eggshell in the mortar. Fill distributively of the 5 beakers with 20 cm3 of hydrochloric acid measured by glass pipette. kick in 0. 5 g of eggshell dust to each beaker, measured by balance. While the answer of eggshell with acid occurs, prepare the buret and clamp for titration. work sure they are clean. Pour NaOH solution into the buret to the 0 level. Make sure all of the eggshell reacted with the HCl. If not, you can help the reaction by using the baguette.Put two drops of phenolophateine into each beaker using the plastic pipette. Take the set-back beaker and titrate the excess of hydrochloric acid. When the solution starts to be pinkish, record the volume of titrated NaOH. make full the buret to the 0 level and repeat the procedure for each beaker. Remember to record the results. Remember to be careful and to leave your workplace clean selective information Collection Table 2. Raw data. The weight of eggshell reacting with HCl and titrated NaOH. Number of effort 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 lowly 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 too large and punic uncertainties in further calculations in which theyre calculated according to formulas in suit of division and multiplication =dA/A+dB/B, where d is boilers suit uncertainty, dA is uncertainty of A and dB is uncertainty of B in case of addition and subtraction d=dA+dB, where where d is boilers suit uncertainty, dA is uncertainty of A and dB is uncertainty of B Trials 2 and 3 were r ejected because of too large differentiation of results. Data treat Two reactions occured in the experiment. Firstly, the HCl reacted with CaCO3 and secondly, the excess of HCl was neutralized by NaOH. 2HCl + CaCO3 CaCl2 + CO2 + piddle HCl + NaOH NaCl + H2O 1. figure the amount of HCl at the beginning 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 amount 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 amount 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 molar ratio in the reaction between HCl and CaCO3 is 2/1, which marrow that 2 moles of HCl react with 1 mole of CaCO3. If 0. 010 moles of HCl reacted with CaCO3 then in that location was 0. 05 mole of CaCO3 in the eggshell. nCaCO3 = 0. 010/2 = 0. 0050. 0075 5. Calculating the constituent of CaCO3 in the eggshell. MCaCO3 = 40. 09 + 12. 01 + 3 * 16,00 = 100. 1 gmol-1 nCaCO3 = 0. 005 mol 0. 0075 m = M * n m = 0. 005*100. 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 quantify Value doubtfulness 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 collected data it is 100%, which suggests that percentage error was not big and remains in accepted valuate of 20%. percentage error = (theore tical value experimental value ? theoretical value) x 100% = (95. 5 100 ? 95. 5) = 4 % finishing 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 appliance to give hens embryo the best possible environment for development. Apart from calcium carbonate, there are other components of eggshell, for archetype milligram carbonate and calcium phosphate which also 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 resembling number of hydrogen ions which can be neutralized, but the second reaction, of magnesium carbonate and hydrochloric acid MgCO3 + 2HCl MgCl2 + CO2 + H2O also takes HCl to its reaction, decreases number of H+ ions and so suggests that much HCl reacted with calcium carbonate. This is the uncontrolled variable, the impurity of the eggshell, which affected 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 school laboratory, but still, the titration is made by baseball mitt and by eye, which may make mistakes although back titration is the best possible appearance in school laboratory to check the amount of particular 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 substance is put into gas chromatograph.The mobile phase, in which the particles of substances move towards the stationary phase is made of unre active gas, such as nitrogen or helium. In this, the substance is separated into particular components and then, the mass spectrometer analyses the components to key out them. This method is commonly used to determine the ingredients of substances, of food, beverages, perfumes. Also, it is useful in treat and and in exploring Universe, for example, one GC-MS was taken by Curiosity to examine the come in of Mars. Summing up in school laboratory, the true 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. spur 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 generally more accurate methods are created, using machines which exclude the human factor from experiments, for example gas chromatography mass spectrometry. Bibliography http//antoine. frostburg. edu/chem/sen ese/101/consumer/faq/eggshell-composition. shtml 18th November 2012 J. Green, S. Damji Chemistry IBID 2008