Monday, June 3, 2019

Experiment of Calcium Carbonate Composition of Eggshells

Experiment of Calcium Carbonate Composition of EggshellsINTRODUCTIONCalcium change, CaCO3, is found in nature giving hardness and strength to things such as seashells, rocks, and peltshells. As hard as this substance is, it will react readily with hydrochloric acid to accede carbon dioxide gas (and both other products). In this experiment students will design an experiment by reacting casings with 2 M HCl to comp atomic tot up 18 the calcium change composition of white (chicken) ballshells to brown eggshells.A good smell eggshell will contain, on average, 2.2 grams of calcium in the form of calcium carbonate. Approximately 94% of a dry eggshell is calcium carbonate and has a typical mass of 5.5 grams,1 although these values brush off differ depending on sources. Amounts as low as 78% have been published. The remaining mass is composed largely of phosphorus and magnesium, and trace amounts of sodium, potassium, zinc, manganese, iron, and copper. In the case of brown versus w hite eggs, a definitive variety in calcium carbonate amounts may be hard to uncover. However, consider this. The color of the eggs is nothing more than than a result of a variant breed. The quality, nutritional value, and taste are identical between white and brown eggs, though two notable differences are size and price. Brown eggs are usually larger and slightly more expensive. The reason for the price increase is because brown eggs come from larger hens, which need to be fed more food daily. With a larger intake of calcium each day, one might expect the produced egg to have a higher calcium carbonate content. However, since the eggs are larger, it must be kept in mind that the calcium is spread over a larger surface area during egg formation. A brown eggshells increased tendency to break, when compared to white, is often attributed to this thinning out of calcium during deposition.To avoid the breakage of eggs before reaching market, the eggshells needs to be as strong as possi ble. The strength of eggshells is mainly determined by the percentage of calcium carbonate in it. In order to monitor the quality of eggshells, the following experiment has to be done to determine the percentage of calcium carbonate in eggshells. In this experiment, back titration is use. First, excess acid is reacted with the calcium carbonate in eggshells.2HCl(aq)+CaCO3(s)CaCl2(aq)+ water(l)+CO2(g)Later, if we can find out the number of mole of unreacted acid, number of mole of calcium carbonate can then be found out. The number of mole of unreacted acid can be found by titration with the following reaction.HCl(aq)+NaOH(aq)H2O(l)+NaCl(aq)Percentage by mass of calcium carbonate in eggshell can then be calculated by the following formula4.2AIMS AND OBJECTIVESThe purpose of this experiment is to determine the percentage by mass of calcium carbonate in eggshells.design an experiment that quantifies the amount of calcium carbonate present in a naturalsubstance.relate the amount of a re actant or product of a chemical reaction to another reactant or product.work collaboratively with their peers to solve a given problem in the laboratory in a way that models the scientific method.apply a common acid reaction between hydrochloric acid and the carbonate ion.Chapter 2THEORY METHOLOGYPRINCIPLE OF THE EXPERIMENTDuring this experiment, the percentage of CaCO3 in an eggshell is determined by reacting the eggshell with hydrochloric acid. The equation for this reaction is2HCl (aq) + CaCO3(s)Ca2+ (aq) + CO2 (g) + H2O (l) + 2Cl- (aq)This reaction cannot be used directly titrate with the CaCO3. Instead, an excess of hydrochloric acid is added to answer the eggshell, and the remaining acid is titrated with NaOH solution to determine the amount of acid that did not react with the eggshell. The equation used to determine the amount of leftover acid isHCl (aq) + NaOH (aq) H2O (l) + Na+ (aq) + Cl- (aq)APPARATUS AND EQUIPMENTSBeaker Pipette FillerElectronicbalanceVolumetric flaskB uretteWash bottleMortar and pestle Conical flasksWhite tileFilter funnelFiltter typography 25.00 cm3 pipetteCHEMICALS USED2 M HCl Phenolphthalein2 M NaOHPROCEDUREWhite and Red colour eggshells have taken and the protein tissue layer was removed on the inside of the eggshells.The eggshell was washed with distilled waterDried in an oven for few minutes.The eggshell was then grounded into fine powder by trench mortar and pestle.2g of eggshell powder is tilted accurately by using an electronic balance and it was transferred to a conical flask.25.00 cm3 of HCl was pipetted to dissolve the eggshell powder.Distilled water was added to the flask until it reached intimately 100cm3. The flask was swirled gently.Put the solution into cubed for two days.Faltered the solution using filter papers.Pippet out 25.00 cm3 from each solutions to titration flasks.The solution was then titrated with standardized NaOH.Repeat another two samples from each solution.Collect the correct burette readings a t the end point.Chapter 3EXPERIMENTAL RESULTSTHE COLOR CHANGE OF THE SOLUTIONWhite egg Brown eggColourless pink Colourless pinkTHE TITRATION RESULT OF BROWN EGG123Volume of eggshells solution/cm325.0025.0025.00Volume of NaOH used/cm320.1019.9020.10 number quite a little of NaOH used (20.10+19.90+20.10) = 20.03cm33THE TITRATION RESULT OF WHITE EGG123Volume of eggshells solution/cm325.0025.0025.00Volume of NaOH used/cm320.4020.3520.00*Average volume of NaOH used (20.40+20.35+20.00) =20.25cm33Chapter 4CALCULATIONSCALCULATIONS2HCl (aq) + CaCO3(s)Ca2+ (aq) + CO2 (g) + H2O (l) + 2Cl- (aq)HCl (aq) + NaOH (aq) H2O (l) + Na+ (aq) + Cl- (aq)FOR BROWN EGG progeny of moles of NaOH used to react with HCl=20.03cm3 /1000) X2M = 40.06X 10-3 molSince number of moles of NaOH = number of moles of HCl in 25cm3=40.06 X 10-3 molHCl mols in 100cm3 = 40.06 X 10-3 X 4 molThe initial no of moles of HCl volume X molarity= 100/1000 X2M = 200X10-3 molNumber of moles of HCl used to react with CaCO3 =( 200X10-3 160.24X 10-3) mol = 39.76X10-3 molAccording to the equation, one mole of HCI required to react with 2 moles of CaCO3,Number of moles of CaCO3 reacted =39.76X10- 3 /2= 19.88X10-3 molThe weight of CaCO3 = 19.88X10-3g X100gThe % of CaCO3 in eggshell (brown) = (1.988/2) X100%=99.4%FOR WHITE EGGNumber of moles of NaOH used to react with HCl(20.25cm3/1000)X2 = 40.50X10-3molSince number of moles of NaOH=number of moles of HCl in 25cm3= 4.50X10-3molHCl Volume in 100cm3 = 40.50 X10-3 X4 molThe initial moles of HCl volume X molarity= 100/1000 X2M = 200X10-3 molNumber of moles of HCl used to react with CaCO3 ( 200X10-3 162X10-3) mol = 38X10-3 molNumber of moles of CaCO3 reacted =38X10-3/2= 19X10-3 molThe weight of CaCO3 = 19X10-3g X100The % of CaCO3 in eggshell (white) = (1.9/2) X100%=95.0%Chapter 5 interchange AND CONCLUTIONCONCLUSIONPercentage of CaCO3 in red eggshells= 99.4%Percentage of CaCO3 in white eggshells= 95.0%Therefore red eggshells has the higher percentage of CaCO3.DISCUSSIONS ource of errorsThe eggshell powder did not dissolve completelyVariation in visual judgment at the end pointInstrumental errors of the electronic balanceThe eggshell was not fully driedSome droplets of solution may still adhere on the beaker and the glass rod which lead to the drop-off in number of moles of excess HClIn this Experiment we can also do the EDTA titration.REFERENCEShttp//www.google.lk/search?hl=ensource=hpq=caco3+percentage+in+eggshellbtnG=Google+Searchmeta=aq=foq=http//wwwchem.csustan.edu/chem1102/Egg.htmhttp//www.oppapers.com/essays/Determine-Percentage-Mass-Calcium-Carbonate-Eggshells/165593http//ag.ansc.purdue.edu/poultry/multistate/koelkebeck1.htm

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.