- 1 4.1INTRODUCTION
- 2 4.2AIMS AND OBJECTIVES
- 3 Chapter 2
- 4 5.THEORY & A ; METHOLOGY
- 5 5.1PRINCIPLE OF THE EXPERIMENT
- 6 5.2APPARATUS AND EQUIPMENTS
- 7 Mortar and pestle Conical flasksWhite tile
- 8 Filter funnelFiltter paper25.00 cm3 pipette
- 9 5.3CHEMICAL USED
- 10 2 M HCl Phenolphthalein
- 11 2 M NaOH
- 12 5.4PROCEDURE
- 13 Chapter 3
- 14 6.EXPERIMENTAL Consequence
- 15 6.1THE COLOR CHANGE OF THE SOLUTION
- 16 6.2THE TITRATION RESULT OF BROWN EGG
- 17 6.3THE TITRATION RESULT OF WHITE EGG
- 18 1
- 19 2
- 20 3
- 21 Volume of eggshells solution/cm3
- 22 25.00
- 23 25.00
- 24 25.00
- 25 Volume of NaOH used/cm3
- 26 20.40
- 27 20.35
- 28 20.00
- 29 Chapter 4
- 30 7.CLCULATIONS
- 31 7.1CALCULATIONS
- 32 7.1.1 FOR BROWN EGG
- 33 7.1.2 FOR WHITE EGG
- 34 Chapter 5
- 35 8.DISCUSSION AND CONCLUTION
- 36 8.1CONCLUSION
- 37 8.2DISCUSSION
- 38 Beginning of mistakes
- 39 9. Reference
Calcium carbonate, CaCO3, is found in nature giving hardness and strength to things such as seashells, stones, and eggshells. Equally difficult as this substance is, it will respond readily with hydrochloric acid to give C dioxide gas ( and two other merchandises ) . In this experiment pupils will plan an experiment by responding eggshells with 2 M HCl to compare the Ca carbonate composing of white ( poulet ) eggshells to brown eggshells.
A good quality eggshell will incorporate, on norm, 2.2 gms of Ca in the signifier of Ca carbonate. Approximately 94 % of a dry eggshell is calcium carbonate and has a typical mass of 5.5 grams,1 although these values can differ depending on beginnings. Sums every bit low as 78 % have been published. The staying mass is composed mostly of P and Mg, and hint sums of Na, K, Zn, manganese, Fe, and Cu. In the instance of brown versus white eggs, a unequivocal difference in Ca carbonate sums may be difficult to bring out. However, see this. The colour of the eggs is nil more than a consequence of a different strain. The quality, nutritionary value, and gustatory sensation are indistinguishable between white and brown eggs, though two noteworthy differences are size and monetary value. Brown eggs are normally larger and somewhat more expensive. The ground for the monetary value addition is because brown eggs come from larger biddies, which need to be fed more nutrient daily. With a larger consumption of Ca each twenty-four hours, one might anticipate the produced egg to hold a higher Ca carbonate content. However, since the eggs are larger, it must be kept in head that the Ca is spread over a larger surface country during egg formation. A brown eggshell ‘s increased inclination to interrupt, when compared to white, is frequently attributed to this “thinning out” of Ca during deposition.
To avoid the breakage of eggs before making market, the eggshells needs to be every bit strong as possible. The strength of eggshells is chiefly determined by the per centum of Ca carbonate in it. In order to supervise the quality of eggshells, the undermentioned experiment has to be done to find the per centum of Ca carbonate in eggshells.
In this experiment, back titration is used. First, extra acid is reacted with the Ca carbonate in eggshells.
2HCl ( aq ) +CaCO3 ( s ) >CaCl2 ( aq ) +H2O ( cubic decimeter ) +CO2 ( g )
Subsequently, if we can happen out the figure of mole of unreacted acid, figure of mole of Ca carbonate can so be found out. The figure of mole of unreacted acid can be found by titration with the undermentioned reaction.
HCl ( aq ) +NaOH ( aq ) >H2O ( cubic decimeter ) +NaCl ( aq )
Percentage by mass of Ca carbonate in eggshell can so be calculated by the undermentioned expression:
4.2AIMS AND OBJECTIVES
The intent of this experiment is to find the per centum by mass of Ca carbonate in eggshells.
design an experiment that quantifies the sum of Ca carbonate nowadays in a natural
- associate the sum of a reactant or merchandise of a chemical reaction to another reactant or merchandise.
- work collaboratively with their equals to work out a given job in the research lab in a manner that theoretical accounts the scientific method.
- use a common acid reaction between hydrochloric acid and the carbonate ion.
5.THEORY & A ; METHOLOGY
5.1PRINCIPLE OF THE EXPERIMENT
During this experiment, the per centum of CaCO3 in an eggshell is determined by responding the eggshell with hydrochloric acid. The equation for this reaction is:
2HCl ( aq ) + CaCO3 ( s ) >Ca2+ ( aq ) + CO2 ( g ) + H2O ( cubic decimeter ) + 2Cl- ( aq )
This reaction can non be used straight titrate with the CaCO3. Alternatively, an surplus of hydrochloric acid is added to fade out the eggshell, and the staying acid is titrated with NaOH solution to find the sum of acid that did non respond with the eggshell. The equation used to find the sum of remnant acid is:
HCl ( aq ) + NaOH ( aq ) > H2O ( cubic decimeter ) + Na+ ( aq ) + Cl- ( aq )
5.2APPARATUS AND EQUIPMENTS
eaker Pipette FillerElectronicbalance
Volumetric flaskBuretteWash bottle
Mortar and pestle Conical flasksWhite tile
Filter funnelFiltter paper25.00 cm3 pipette
2 M HCl Phenolphthalein
2 M NaOH
- White and Red coloring material eggshells have taken and the protein membrane was removed on the interior of the eggshells.
- The eggshell was washed with distilled H2O
- Dried in an oven for few proceedingss.
- The eggshell was so grounded into all right pulverization by howitzer and stamp.
- 2g of eggshell pulverization is weighted accurately by utilizing an electronic balance and it was transferred to a conelike flask.
- 25.00 cm3 of HCl was pipetted to fade out the eggshell pulverization.
- Distilled H2O was added to the flask until it reached about 100cm3. The flask was swirled gently.
- Put the solution into cubed for two yearss.
- Faltered the solution utilizing filter documents.
- Pippet out 25.00 cm3 from each solutions to titration flasks.
- The solution was so titrated with standardised NaOH.
- Repeat another two samples from each solution.
- Roll up the right burette readings at the terminal point.
6.1THE COLOR CHANGE OF THE SOLUTION
White egg Brown egg
Colourless pink Colourless pink
6.2THE TITRATION RESULT OF BROWN EGG
Volume of eggshells solution/cm3
Volume of NaOH used/cm3
- Average volume of NaOH used: ( 20.10+19.90+20.10 ) = 20.03cm33
6.3THE TITRATION RESULT OF WHITE EGG
Volume of eggshells solution/cm3
Volume of NaOH used/cm3
*Average volume of NaOH used: ( 20.40+20.35+20.00 ) =20.25cm33
- 2HCl ( aq ) + CaCO3 ( s ) >Ca2+ ( aq ) + CO2 ( g ) + H2O ( cubic decimeter ) + 2Cl- ( aq )
- HCl ( aq ) + NaOH ( aq ) > H2O ( cubic decimeter ) + Na+ ( aq ) + Cl- ( aq )
7.1.1 FOR BROWN EGG
Number of moles of NaOH used to respond with HCl
=20.03cm3 /1000 ) X2M = 40.06X 10-3 mol
Since figure of moles of NaOH = figure of moles of HCl in 25cm3
=40.06 X 10-3 mol
HCl mols in 100cm3 = 40.06 Ten 10-3 Ten 4 mol
The initial no of moles of HCl: volume X molar concentration
= 100/1000 X2M = 200X10-3 mol
Number of moles of HCl used to respond with CaCO3 =
( 200X10-3 – 160.24X 10-3 ) mol = 39.76X10-3 mol
Harmonizing to the equation, one mole of HCI required to respond with 2 moles of CaCO3,
Number of moles of CaCO3 reacted =39.76X10- 3 /2
= 19.88X10-3 mol
The weight of CaCO3 = 19.88X10-3g X100g
The % of CaCO3 in eggshell ( brown ) = ( 1.988/2 ) X100 %
7.1.2 FOR WHITE EGG
Number of moles of NaOH used to respond with HCl:
( 20.25cm3/1000 ) X2 = 40.50X10-3mol
Since figure of moles of NaOH=number of moles of HCl in 25cm3
HCl Volume in 100cm3 = 40.50 X10-3 X4 mol
The initial moles of HCl: volume X molar concentration
= 100/1000 X2M = 200X10-3 mol
Number of moles of HCl used to respond with CaCO3:
( 200X10-3 – 162X10-3 ) mol = 38X10-3 mol
Number of moles of CaCO3 reacted =38X10-3/2
= 19X10-3 mol
The weight of CaCO3 = 19X10-3g X100
The % of CaCO3 in eggshell ( white ) = ( 1.9/2 ) X100 %
8.DISCUSSION AND CONCLUTION
- Percentage of CaCO3 in ruddy eggshells= 99.4 %
- Percentage of CaCO3 in white eggshells= 95.0 %
Therefore ruddy eggshells has the higher per centum of CaCO3.
Beginning of mistakes
- The eggshell pulverization did non fade out wholly
- Variation in ocular judgement at the terminal point
- Instrumental mistakes of the electronic balance
- The eggshell was non to the full dried
- Some droplets of solution may still adhere on the beaker and the glass rod which lead to the decrease in figure of moles of extra HCl
In this Experiment we can besides make the EDTA titration.
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