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GROUP MEMBERS: BIBI KHAN, BRITTNEY BARRINGTON
Content Page Content
Page No.
PROPOSAL Statement of Problem Variables Apparatus/Materials/Reagents Methodology IMPLEMENTATION
Page | 1
Page | 2
Statement of problem A gardener noticed that his crops were susceptible to root disease, stunted growth and discolored leaves, which were all effects of calcium deficiency. He decided to add egg shells to the soil to reduce this problem. However, he was indecisive when choosing the egg shells because he wanted to select the appropriate egg shell to supply the plants with maximum calcium for better growth. His grandmother told him brown egg shell contains a larger amount of calcium carbonate than white egg, while his brother told him both contains the amount of calcium carbonate. Plan and design an experiment to investigate the calcium carbonate concentration in white and brown egg shells.
Title: Back Titration
Hypothesis Brown egg shells have a higher concentration of calcium carbonate than white egg shells.
Aim: To determine, compare and indicate whether brown egg shell has a higher concentration of calcium carbonate than white egg shell.
Page | 3
Background Information Calcium carbonate, more commonly known as calcitic lime or garden lime, has long been a staple in garden, field, and lawn management. They are four major benefits of adding calcium carbonate to the soil. These include: correct soil pH, increasing the efficacy of other nutrients, adding calcium and reducing toxicity of metals in the soil. Calcium carbonate is an excellent product for raising the pH of soil. Most plants do best in soils with a pH between 5.5 and 6.5 (Maximum Yield, 2019). Calcium carbonate can be broadcast over and incorporated into soils in need of a dose of alkalinity. Calcium carbonate is a great source of calcium (Ca). Calcium is an important nutrient that strengthens a plant’s cellular walls and is vital in new cell development. Besides being potentially toxic for humans, heavy metals can be toxic to plants as well. Calcium carbonate does not eliminate the metals from the soil, but “ties them up” so that they are not as available for uptake by plants (Thompson, 2007). One of the many unseen benefits of using calcium carbonate, as it relates to its ability to adjust soil pH, is its role in making nutrients available to plants. All of the nutrients that a plant needs may be present in a soil, but they may be unavailable to plants (Nutrient Lockout, 2010). If the pH is not conducive for the plant to easily “grab a hold” of then majority of nutrients that a plant needs are most available to plants at the aforementioned 5.5 to 6.5 pH range.
STUFF NEED TO BE ADDED BAsED ON TITRATION
Page | 4
Variables Controlled Variable o
The concentration of Hydrochloric acid used
o
The concentration of Sodium Hydroxide used
o
The Volume of HCl used to dissolve the egg shell
o
The mass of egg shell used.
o
The volume of water used to dilute the solution
o
The indicator used
o
The volume of mixture (HCl and egg shell) used
Independent Variable o
The brown egg shells
o
The white egg shells
Dependent Variable o
The volume of Sodium Hydroxide used.
Page | 5
Apparatus o Funnel [1] o Beaker [3] o Pipette [3] o Dropper [3] o Electronic balance [1] o Volumetric flask [2] o Burette [2] o Wash bottle [1] o Mortar and pestle [1] o Conical flasks [8]
Reagents o Phenolphthalein o 1.0 M Hydrochloric Acid o 0.1 M Sodium Hydroxide
Materials o White Egg [2] o Brown Egg [2]
Page | 6
Methodology 1. Gather the materials, reagents and apparatus listed. 2. Obtain four brown and four white eggs. 3. Wash and boil the eggs for ten minutes. 4. Peel the eggs and ensure to obtain the shell without the membrane. 5. Dry the egg shell. 6. Grind the brown egg shell with a mortar in a pestle. 7. Weigh 1.0 grams of the egg shell. 8. Measure 50ml of 1.0 moldm-3 hydrochloric acid and transfer it to a beaker. 9. Add the weighed egg shell to the acid and heat it gently. 10.After effervescence stops, transfer the solution to a 250ml volumetric flask and make up to the mark with distilled water.
11.Pipette 20 ml of the solution into four conical flasks labeling rough, trial 1, 2 and 3. 12.Add two drops of phenolphthalein indicator to each flask. 13.Fill a beaker with about 100 mL of 0.100 M sodium hydroxide. Using a funnel, add the solution to a clean burette to rinse it. Empty the burette into the sink. Fill the burette with the sodium hydroxide solution to just above the top mark. . Run some solution out to remove and record the volume reading.
14.Titrate the NaOH against the rough, while swirling the conical flask. 15.At the sight if the persistent pink color add the remaining NaOH dropwise (or by half drops) until the colour remains for at least 30 sec.
Page | 7
16. Read and record the final volume to ±0.01 mL. 17.Repeat the titration for trials 1, 2 and 3. 18. Repeat steps 3 to 17 using the white egg shell. 19.Tabulate all volume readings recorded. 20.Calculate the percent calcium carbonate in each sample. The major component of eggshells is calcium carbonate (CaCO3 ).
Page | 8
Page | 9
Title: Back Titration
Hypothesis Brown egg shells have a higher concentration of calcium carbonate than white egg shells.
Aim: To determine, compare and indicate whether brown egg shell has a higher concentration of calcium carbonate than white egg shell.
Page | 10
Background Information Calcium carbonate, more commonly known as calcitic lime or garden lime, has long been a staple in garden, field, and lawn management. They are four major benefits of adding calcium carbonate to the soil. These include: correct soil pH, increasing the efficacy of other nutrients, adding calcium and reducing toxicity of metals in the soil. Calcium carbonate is an excellent product for raising the pH of soil. Most plants do best in soils with a pH between 5.5 and 6.5 (Maximum Yield, 2019). Calcium carbonate can be broadcast over and incorporated into soils in need of a dose of alkalinity. Calcium carbonate is a great source of calcium (Ca). Calcium is an important nutrient that strengthens a plant’s cellular walls and is vital in new cell development. Besides being potentially toxic for humans, heavy metals can be toxic to plants as well. Calcium carbonate does not eliminate the metals from the soil, but “ties them up” so that they are not as available for uptake by plants (Thompson, 2007). One of the many unseen benefits of using calcium carbonate, as it relates to its ability to adjust soil pH, is its role in making nutrients available to plants. All of the nutrients that a plant needs may be present in a soil, but they may be unavailable to plants (Nutrient Lockout, 2010). If the pH is not conducive for the plant to easily “grab a hold” of then majority of nutrients that a plant needs are most available to plants at the aforementioned 5.5 to 6.5 pH range.
STUFF NEED TO BE ADDED BAsED ON TITRATION
Page | 11
Variables Controlled Variable o
The concentration of Hydrochloric acid used
o
The concentration of Sodium Hydroxide used
o
The Volume of HCl used to dissolve the egg shell
o
The mass of egg shell used.
o
The volume of water used to dilute the solution
o
The indicator used
o
The volume of mixture (HCl and egg shell) used
Independent Variable o
The brown egg shells
o
The white egg shells
Dependent Variable o
The volume of Sodium Hydroxide used.
Page | 12
Apparatus o Funnel [1] o Beaker [3] o Pipette [3] o Dropper [3] o Electronic balance [1] o Volumetric flask [2] o Burette [2] o Wash bottle [1] o Mortar and pestle [1] o Conical flasks [8]
Reagents o Phenolphthalein o 1.0 M Hydrochloric Acid o 0.1 M Sodium Hydroxide
Materials o White Egg [2] o Brown Egg [2]
Page | 13
Methodology 21.Gather the materials, reagents and apparatus listed. 22.Obtain four brown and four white eggs. 23.Wash and boil the eggs for ten minutes. 24.Peel the eggs and ensure to obtain the shell without the membrane. 25.Dry the egg shell. 26.Grind the brown egg shell with a mortar in a pestle. 27.Weigh 1.0 grams of the egg shell. 28.Measure 50ml of 1.0 moldm-3 hydrochloric acid and transfer it to a beaker. 29.Add the weighed egg shell to the acid and heat it gently. 30.After effervescence stops, transfer the solution to a 250ml volumetric flask and make up to the mark with distilled water.
31.Pipette 20 ml of the solution into four conical flasks labeling rough, trial 1, 2 and 3. 32.Add two drops of phenolphthalein indicator to each flask. 33.Fill a beaker with about 100 mL of 0.100 M sodium hydroxide. Using a funnel, add the solution to a clean burette to rinse it. Empty the burette into the sink. Fill the burette with the sodium hydroxide solution to just above the top mark. . Run some solution out to remove and record the volume reading.
34.Titrate the NaOH against the rough, while swirling the conical flask. 35.At the sight if the persistent pink color add the remaining NaOH dropwise (or by half drops) until the colour remains for at least 30 sec.
Page | 14
36. Read and record the final volume to ±0.01 mL. 37.Repeat the titration for trials 1, 2 and 3. 38. Repeat steps 3 to 17 using the white egg shell. 39.Tabulate all volume readings recorded. 40.Calculate the percent calcium carbonate in each sample. The major component of eggshells is calcium carbonate (CaCO3 ).
Page | 15
Results
Table 1 White Egg Shell BURETTE VOLUME READINGS
TRIALS ROUGH
[cm3]
1
2
3
0.0
0.0
0.0
0.0
FINAL READING
29.7
29.3
29.3
29.2
VOLUME OF TITRE
29.7
29.3
29.3
29.2
INITIAL READING
THE TABLE ABOVE SHOWS THE INITIAL READING, FINAL READING AND VOLUME OF TITRE FOR THE ROUGH, TRIALS 1,2 AND 3 WHEN TITRATING THE SODIUM HYDROXIDE AGAINST THE WHITE EGG SHELL.
Calculations:
FOR WHITE EGG SHELLS Average Volume of NaOH used: (29.3 + 29.3 + 29.2) =87.8/3 = 29.3cm3 1. Calculating the number of moles of NaOH used to react with HCl Mol of NaOH = Avg. volume of NaOH * Concentration of NaOH 29.3dm3/1000 * 0.1 moldm3 = 0.00293 mol 2. Calculating the moles of HCl that reacted with the NaOH HCl (aq) +NaOH (aq) →H2O (l) + NaCl (aq) Mol of HCl = 0.00293 mol (since 1 mol of NaOH reacts with 1 mol HCl)
Page | 16
No. of Moles of HCl in 20ml = 0.00293mol x 250/20 =0.036625 mol 3. Calculating the number of moles of HCl initially added (original no. of mol): Moles of HCl = volume of HCl * concentration of HCl Moles of HCl = 50dm3/1000 * 1.0moldm3 = 0.05 mol 4. Calculating the number of moles of HCl that reacted with the CaCO3 0.05 mol – 0.036625 mol = 0.013375mol 5. Calculating the number of moles of Calcium carbonated that reacted 2HCl (aq) + CaCO3(s) →CaCl2 (aq) + H2O (l) + CO2 (g) 0.013375 mol/2 = 0.0066875 mol (Since 2 mol of HCl reacts with 1 mol CaCO3) 6. The molar mass of CaCO3 = (40 + 12 + 16 + 16 + 16) = 100g/mol The mass of CaCO3 = No. of mole of CaCO3 * Molar mass of CaCO3 = 0.0066875 mol X100g = 0.66875g The percentage of CaCO3 in eggshell (white) = Mass of CaCO3/ mass of shells * 100 = (0.66875/1.0g * 100) =66.9 CaCO3 %
Page | 17
Table 2 Brown Egg Shell BURETTE VOLUME READINGS
TRIALS ROUGH
[cm3]
1
2
3
0.0
0.0
0.0
0.0
FINAL READING
29.9
29.0
29.0
28.9
VOLUME OF TITRE
29.9
29.0
29.0
28.9
INITIAL READING
THE TABLE ABOVE SHOWS THE INITIAL READING, FINAL READING AND VOLUME OF TITRE FOR THE ROUGH, TRIALS 1,2 AND 3 WHEN TITRATING THE SODIUM HYDROXIDE AGAINST THE BROWN EGG SHELL.
Calculations:
FOR BROWN EGG SHELLS Average Volume of NaOH used: (29.0 + 29.0 + 28.9) = 86.9/3 = 28.97cm3 1. Calculating the number of moles of NaOH used to react with HCl Mol of NaOH = volume of NaOH * concentration of NaOH 28.97dm3/1000 * 0.1 moldm3 = 0.00289 mol 2. Calculating the moles of HCl that reacted with this HCl (aq) +NaOH (aq) →H2O (l) + NaCl (aq) Mol of HCl = 0.00289 mol (since 1 mol of NaOH reacts with 1 mol HCl)
Page | 18
No. of mole in 20 ml of HCl = ( 0.00289 * 250/20 ) = 0.036213 3. Calculating the number of moles of HCl initially added: Moles of HCl = volume of HCl * concentration of HCl Moles of HCl = 50dm3/1000 * 1.0moldm3 = 0.05 mol 4. Calculating the number of moles of HCl that reacted with the CaCO3 0.05 mol – 0.036213 mol = 0.013788 mol 5. Calculating the number of moles of Calcium carbonated that reacted 2HCl (aq) + CaCO3(s) →CaCl2 (aq) + H2O (l) + CO2 (g) 0.013788mol/2 = 0.006894 mol (Since 2 mol of HCl reacts with 1 mol CaCO3) 6. The molar mass of CaCO3 = (40 + 12 + 16 + 16 + 16) = 100g/mol The mass of CaCO3 = No. of mole of CaCO3 * Molar mass of CaCO3 = 0.006894 mol X100g = 0.6894g The percentage of CaCO3 in eggshell (white) = Mass of CaCO3/ mass of shells * 100 = (0.6894g/1.0g * 100) = 68.9 CaCO3%
Page | 19
Discussion
Sources of Error Limitation Precautions
Recommendations Conclusion
Page | 20
Content Page Content
Page No.
PROPOSAL Statement of Problem Variables Apparatus/Materials/Reagents Methodology IMPLEMENTATION
Page | 1
Page | 2
Statement of problem A gardener noticed that his crops were susceptible to root disease, stunted growth and discolored leaves, which were all effects of calcium deficiency. He decided to add egg shells to the soil to reduce this problem. However, he was indecisive when choosing the egg shells because he wanted to select the appropriate egg shell to supply the plants with maximum calcium for better growth. His grandmother told him brown egg shell contains a larger amount of calcium carbonate than white egg, while his brother told him both contains the amount of calcium carbonate. Plan and design an experiment to investigate the calcium carbonate concentration in white and brown egg shells.
Title: Back Titration
Hypothesis Brown egg shells have a higher concentration of calcium carbonate than white egg shells.
Aim: To determine, compare and indicate whether brown egg shell has a higher concentration of calcium carbonate than white egg shell.
Page | 3
Background Information Calcium carbonate, more commonly known as calcitic lime or garden lime, has long been a staple in garden, field, and lawn management. They are four major benefits of adding calcium carbonate to the soil. These include: correct soil pH, increasing the efficacy of other nutrients, adding calcium and reducing toxicity of metals in the soil. Calcium carbonate is an excellent product for raising the pH of soil. Most plants do best in soils with a pH between 5.5 and 6.5 (Maximum Yield, 2019). Calcium carbonate can be broadcast over and incorporated into soils in need of a dose of alkalinity. Calcium carbonate is a great source of calcium (Ca). Calcium is an important nutrient that strengthens a plant’s cellular walls and is vital in new cell development. Besides being potentially toxic for humans, heavy metals can be toxic to plants as well. Calcium carbonate does not eliminate the metals from the soil, but “ties them up” so that they are not as available for uptake by plants (Thompson, 2007). One of the many unseen benefits of using calcium carbonate, as it relates to its ability to adjust soil pH, is its role in making nutrients available to plants. All of the nutrients that a plant needs may be present in a soil, but they may be unavailable to plants (Nutrient Lockout, 2010). If the pH is not conducive for the plant to easily “grab a hold” of then majority of nutrients that a plant needs are most available to plants at the aforementioned 5.5 to 6.5 pH range.
STUFF NEED TO BE ADDED BAsED ON TITRATION
Page | 4
Variables Controlled Variable o
The concentration of Hydrochloric acid used
o
The concentration of Sodium Hydroxide used
o
The Volume of HCl used to dissolve the egg shell
o
The mass of egg shell used.
o
The volume of water used to dilute the solution
o
The indicator used
o
The volume of mixture (HCl and egg shell) used
Independent Variable o
The brown egg shells
o
The white egg shells
Dependent Variable o
The volume of Sodium Hydroxide used.
Page | 5
Apparatus o Funnel [1] o Beaker [3] o Pipette [3] o Dropper [3] o Electronic balance [1] o Volumetric flask [2] o Burette [2] o Wash bottle [1] o Mortar and pestle [1] o Conical flasks [8]
Reagents o Phenolphthalein o 1.0 M Hydrochloric Acid o 0.1 M Sodium Hydroxide
Materials o White Egg [2] o Brown Egg [2]
Page | 6
Methodology 1. Gather the materials, reagents and apparatus listed. 2. Obtain four brown and four white eggs. 3. Wash and boil the eggs for ten minutes. 4. Peel the eggs and ensure to obtain the shell without the membrane. 5. Dry the egg shell. 6. Grind the brown egg shell with a mortar in a pestle. 7. Weigh 1.0 grams of the egg shell. 8. Measure 50ml of 1.0 moldm-3 hydrochloric acid and transfer it to a beaker. 9. Add the weighed egg shell to the acid and heat it gently. 10.After effervescence stops, transfer the solution to a 250ml volumetric flask and make up to the mark with distilled water.
11.Pipette 20 ml of the solution into four conical flasks labeling rough, trial 1, 2 and 3. 12.Add two drops of phenolphthalein indicator to each flask. 13.Fill a beaker with about 100 mL of 0.100 M sodium hydroxide. Using a funnel, add the solution to a clean burette to rinse it. Empty the burette into the sink. Fill the burette with the sodium hydroxide solution to just above the top mark. . Run some solution out to remove and record the volume reading.
14.Titrate the NaOH against the rough, while swirling the conical flask. 15.At the sight if the persistent pink color add the remaining NaOH dropwise (or by half drops) until the colour remains for at least 30 sec.
Page | 7
16. Read and record the final volume to ±0.01 mL. 17.Repeat the titration for trials 1, 2 and 3. 18. Repeat steps 3 to 17 using the white egg shell. 19.Tabulate all volume readings recorded. 20.Calculate the percent calcium carbonate in each sample. The major component of eggshells is calcium carbonate (CaCO3 ).
Page | 8
Page | 9
Title: Back Titration
Hypothesis Brown egg shells have a higher concentration of calcium carbonate than white egg shells.
Aim: To determine, compare and indicate whether brown egg shell has a higher concentration of calcium carbonate than white egg shell.
Page | 10
Background Information Calcium carbonate, more commonly known as calcitic lime or garden lime, has long been a staple in garden, field, and lawn management. They are four major benefits of adding calcium carbonate to the soil. These include: correct soil pH, increasing the efficacy of other nutrients, adding calcium and reducing toxicity of metals in the soil. Calcium carbonate is an excellent product for raising the pH of soil. Most plants do best in soils with a pH between 5.5 and 6.5 (Maximum Yield, 2019). Calcium carbonate can be broadcast over and incorporated into soils in need of a dose of alkalinity. Calcium carbonate is a great source of calcium (Ca). Calcium is an important nutrient that strengthens a plant’s cellular walls and is vital in new cell development. Besides being potentially toxic for humans, heavy metals can be toxic to plants as well. Calcium carbonate does not eliminate the metals from the soil, but “ties them up” so that they are not as available for uptake by plants (Thompson, 2007). One of the many unseen benefits of using calcium carbonate, as it relates to its ability to adjust soil pH, is its role in making nutrients available to plants. All of the nutrients that a plant needs may be present in a soil, but they may be unavailable to plants (Nutrient Lockout, 2010). If the pH is not conducive for the plant to easily “grab a hold” of then majority of nutrients that a plant needs are most available to plants at the aforementioned 5.5 to 6.5 pH range.
STUFF NEED TO BE ADDED BAsED ON TITRATION
Page | 11
Variables Controlled Variable o
The concentration of Hydrochloric acid used
o
The concentration of Sodium Hydroxide used
o
The Volume of HCl used to dissolve the egg shell
o
The mass of egg shell used.
o
The volume of water used to dilute the solution
o
The indicator used
o
The volume of mixture (HCl and egg shell) used
Independent Variable o
The brown egg shells
o
The white egg shells
Dependent Variable o
The volume of Sodium Hydroxide used.
Page | 12
Apparatus o Funnel [1] o Beaker [3] o Pipette [3] o Dropper [3] o Electronic balance [1] o Volumetric flask [2] o Burette [2] o Wash bottle [1] o Mortar and pestle [1] o Conical flasks [8]
Reagents o Phenolphthalein o 1.0 M Hydrochloric Acid o 0.1 M Sodium Hydroxide
Materials o White Egg [2] o Brown Egg [2]
Page | 13
Methodology 21.Gather the materials, reagents and apparatus listed. 22.Obtain four brown and four white eggs. 23.Wash and boil the eggs for ten minutes. 24.Peel the eggs and ensure to obtain the shell without the membrane. 25.Dry the egg shell. 26.Grind the brown egg shell with a mortar in a pestle. 27.Weigh 1.0 grams of the egg shell. 28.Measure 50ml of 1.0 moldm-3 hydrochloric acid and transfer it to a beaker. 29.Add the weighed egg shell to the acid and heat it gently. 30.After effervescence stops, transfer the solution to a 250ml volumetric flask and make up to the mark with distilled water.
31.Pipette 20 ml of the solution into four conical flasks labeling rough, trial 1, 2 and 3. 32.Add two drops of phenolphthalein indicator to each flask. 33.Fill a beaker with about 100 mL of 0.100 M sodium hydroxide. Using a funnel, add the solution to a clean burette to rinse it. Empty the burette into the sink. Fill the burette with the sodium hydroxide solution to just above the top mark. . Run some solution out to remove and record the volume reading.
34.Titrate the NaOH against the rough, while swirling the conical flask. 35.At the sight if the persistent pink color add the remaining NaOH dropwise (or by half drops) until the colour remains for at least 30 sec.
Page | 14
36. Read and record the final volume to ±0.01 mL. 37.Repeat the titration for trials 1, 2 and 3. 38. Repeat steps 3 to 17 using the white egg shell. 39.Tabulate all volume readings recorded. 40.Calculate the percent calcium carbonate in each sample. The major component of eggshells is calcium carbonate (CaCO3 ).
Page | 15
Results
Table 1 White Egg Shell BURETTE VOLUME READINGS
TRIALS ROUGH
[cm3]
1
2
3
0.0
0.0
0.0
0.0
FINAL READING
29.7
29.3
29.3
29.2
VOLUME OF TITRE
29.7
29.3
29.3
29.2
INITIAL READING
THE TABLE ABOVE SHOWS THE INITIAL READING, FINAL READING AND VOLUME OF TITRE FOR THE ROUGH, TRIALS 1,2 AND 3 WHEN TITRATING THE SODIUM HYDROXIDE AGAINST THE WHITE EGG SHELL.
Calculations:
FOR WHITE EGG SHELLS Average Volume of NaOH used: (29.3 + 29.3 + 29.2) =87.8/3 = 29.3cm3 1. Calculating the number of moles of NaOH used to react with HCl Mol of NaOH = Avg. volume of NaOH * Concentration of NaOH 29.3dm3/1000 * 0.1 moldm3 = 0.00293 mol 2. Calculating the moles of HCl that reacted with the NaOH HCl (aq) +NaOH (aq) →H2O (l) + NaCl (aq) Mol of HCl = 0.00293 mol (since 1 mol of NaOH reacts with 1 mol HCl)
Page | 16
No. of Moles of HCl in 20ml = 0.00293mol x 250/20 =0.036625 mol 3. Calculating the number of moles of HCl initially added (original no. of mol): Moles of HCl = volume of HCl * concentration of HCl Moles of HCl = 50dm3/1000 * 1.0moldm3 = 0.05 mol 4. Calculating the number of moles of HCl that reacted with the CaCO3 0.05 mol – 0.036625 mol = 0.013375mol 5. Calculating the number of moles of Calcium carbonated that reacted 2HCl (aq) + CaCO3(s) →CaCl2 (aq) + H2O (l) + CO2 (g) 0.013375 mol/2 = 0.0066875 mol (Since 2 mol of HCl reacts with 1 mol CaCO3) 6. The molar mass of CaCO3 = (40 + 12 + 16 + 16 + 16) = 100g/mol The mass of CaCO3 = No. of mole of CaCO3 * Molar mass of CaCO3 = 0.0066875 mol X100g = 0.66875g The percentage of CaCO3 in eggshell (white) = Mass of CaCO3/ mass of shells * 100 = (0.66875/1.0g * 100) =66.9 CaCO3 %
Page | 17
Table 2 Brown Egg Shell BURETTE VOLUME READINGS
TRIALS ROUGH
[cm3]
1
2
3
0.0
0.0
0.0
0.0
FINAL READING
29.9
29.0
29.0
28.9
VOLUME OF TITRE
29.9
29.0
29.0
28.9
INITIAL READING
THE TABLE ABOVE SHOWS THE INITIAL READING, FINAL READING AND VOLUME OF TITRE FOR THE ROUGH, TRIALS 1,2 AND 3 WHEN TITRATING THE SODIUM HYDROXIDE AGAINST THE BROWN EGG SHELL.
Calculations:
FOR BROWN EGG SHELLS Average Volume of NaOH used: (29.0 + 29.0 + 28.9) = 86.9/3 = 28.97cm3 1. Calculating the number of moles of NaOH used to react with HCl Mol of NaOH = volume of NaOH * concentration of NaOH 28.97dm3/1000 * 0.1 moldm3 = 0.00289 mol 2. Calculating the moles of HCl that reacted with this HCl (aq) +NaOH (aq) →H2O (l) + NaCl (aq) Mol of HCl = 0.00289 mol (since 1 mol of NaOH reacts with 1 mol HCl)
Page | 18
No. of mole in 20 ml of HCl = ( 0.00289 * 250/20 ) = 0.036213 3. Calculating the number of moles of HCl initially added: Moles of HCl = volume of HCl * concentration of HCl Moles of HCl = 50dm3/1000 * 1.0moldm3 = 0.05 mol 4. Calculating the number of moles of HCl that reacted with the CaCO3 0.05 mol – 0.036213 mol = 0.013788 mol 5. Calculating the number of moles of Calcium carbonated that reacted 2HCl (aq) + CaCO3(s) →CaCl2 (aq) + H2O (l) + CO2 (g) 0.013788mol/2 = 0.006894 mol (Since 2 mol of HCl reacts with 1 mol CaCO3) 6. The molar mass of CaCO3 = (40 + 12 + 16 + 16 + 16) = 100g/mol The mass of CaCO3 = No. of mole of CaCO3 * Molar mass of CaCO3 = 0.006894 mol X100g = 0.6894g The percentage of CaCO3 in eggshell (white) = Mass of CaCO3/ mass of shells * 100 = (0.6894g/1.0g * 100) = 68.9 CaCO3%
Page | 19
Discussion
Sources of Error Limitation Precautions
Recommendations Conclusion
Page | 20
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