Penentuan Kandungan CaCO3 Dalam Kulit Telur

Summary

This video demonstrates a laboratory experiment for determining the calcium carbonate (CaCO₃) content in eggshells. It begins with the standardization of a magnesium sulfate (MgSO₄) solution, followed by its use in a titration process. The eggshells are dissolved in hydrochloric acid (HCl), and the resulting solution is titrated with NaOH to determine the CaCO₃ concentration. The procedure includes safety protocols, such as working in a fume hood, and emphasizes precise measurement techniques to ensure accurate results. The experiment concludes with calculations based on titration data to determine the CaCO₃ content in the eggshell sample.

Takeaways

• 😀 Introduction by Septian Budiman from the Department of Chemistry, Universitas Negeri Padang, detailing the purpose of the experiment: determining the calcium carbonate (CaCO3) content in eggshells.
• 😀 The first step involves standardizing a solution of MgSO4, where 0.0605 g of MgSO4 is weighed, dissolved in water, and transferred to a volumetric flask.
• 😀 The MgSO4 solution is carefully prepared by rinsing the container and adjusting the volume with distilled water, ensuring accuracy by aligning eye level with the scale during measurement.
• 😀 Buffer solution and NaCl are added to the MgSO4 solution, and the mixture is titrated until it turns blue, marking the endpoint. The volume used during titration is recorded.
• 😀 Eggshells (about 10 eggs) are weighed (around 3 grams), dissolved in 50 mL of hydrochloric acid (HCl), and the process is done in a fume hood due to the hazardous gas release.
• 😀 The dissolved sample is transferred to a larger beaker, rinsed with distilled water, and heated to ensure complete dissolution of the eggshells.
• 😀 After heating, the solution is filtered to remove undissolved particles, and a 25 mL aliquot is transferred to a 250 mL volumetric flask for dilution.
• 😀 The solution is homogenized, and a 25 mL sample is taken for further dilution into a 100 mL volumetric flask to prepare it for titration.
• 😀 In the titration step, 2.5 mL of the diluted sample is taken, and NaOH is added with murexide indicator. The sample is titrated with EDTA until a blue endpoint is reached.
• 😀 The final volume of EDTA used in the titration helps calculate its concentration, which is then used to determine the CaCO3 content in the eggshell sample.
• 😀 The laboratory report must include calculations for the EDTA concentration and the CaCO3 content, along with answers to pre-laboratory questions.

Q & A

What is the main goal of the experiment described in the transcript?

The main goal of the experiment is to determine the calcium carbonate (CaCO₃) content in eggshells using a titration method.

What is the role of MgSO₄ in the standardization process?

MgSO₄ is used as a primary standard solution to standardize the titrant in the experiment, ensuring accurate concentration for subsequent titrations.

How is the MgSO₄ solution prepared for standardization?

The MgSO₄ is weighed, dissolved in a beaker, and then transferred to a volumetric flask. The flask is filled with distilled water up to the calibration mark to ensure accurate concentration.

What precautions should be taken when dissolving eggshells in HCl?

The process of dissolving eggshells in HCl should be performed in a fume hood due to the release of potentially harmful gas bubbles during the reaction.

Why is it important to rinse the beaker and volumetric flask with distilled water during the preparation of MgSO₄ solution?

Rinsing ensures that no MgSO₄ residue remains in the beaker or flask, guaranteeing that the entire amount of substance is used in the solution preparation, preventing inaccuracies.

What is the function of the buffer solution and NaCl in the titration process?

The buffer solution helps maintain a constant pH during titration, while NaCl serves as an indicator to help identify the endpoint of the titration.

How do you know when the endpoint of the titration is reached?

The endpoint is reached when the solution changes color, indicating that the titration reaction has completed. In this case, the solution turns blue at the endpoint.

What should you do after filtering the dissolved eggshell sample?

After filtering, the sample should be transferred into a 250 mL volumetric flask, diluted to the calibration mark with distilled water, and homogenized before use in the titration.

How is the concentration of CaCO₃ in the eggshell sample calculated?

The concentration of CaCO₃ is calculated by titrating the sample with a standard solution (EDTA), using the volume of titrant used and the known concentration of EDTA to determine the moles of CaCO₃.

What are the final steps after completing the titration in this experiment?

After completing the titration, the volume of titrant used is recorded, and the concentration of EDTA is calculated. Using this data, the percentage of CaCO₃ in the eggshell sample is determined.