Praktikum Kimia Dasar Modul 5. Sifat Fisik dan Pemisahan

Summary

The video demonstrates a basic chemistry practicum on physical properties and separation. It covers measuring solids in a liquid sample, chromatography, distillation, Soxhlet extraction, and liquid–liquid separation with a separating funnel.

1. Measuring Solids in a Sample

The stated aims are to determine total solids (TS), total dissolved solids (TDS), and total suspended solids (TSS), and to test for ions in a sample. The demonstration uses orange juice.

• The sample is homogenized, and 50 mL is measured for filtration.
• A clean, dry filter paper is weighed first: 0.391 g.
• The sample is filtered:
  • Material retained on the filter paper is used to measure suspended solids.
  • The filtrate is used to measure dissolved solids.
• A 25 mL portion of filtrate is placed in a pre-weighed beaker and heated at 150°C until the water evaporates. The beaker’s initial mass is 62.903 g, and its mass with the dried residue is 62.992 g.
• The filter paper and retained solids are dried in an oven at 100°C for about 5–10 minutes. Their combined mass after drying is 0.605 g.
• The video does not show the final calculations or the ion-testing procedure.

2. Paper Chromatography

The presenter prepares a developing solvent using 9 mL acetone and 1 mL of 6 M hydrochloric acid.

• Place small spots of different-colored markers on chromatography paper.
• Roll the paper and place it in the solvent chamber, ensuring the lower edge contacts the solvent.
• Close the chamber and allow the colors to travel up the paper.
• Remove the paper when the solvent front reaches the upper limit, then air-dry it or use a hair dryer.
• Mark the separated color bands and measure their travel distances for analysis. The video indicates that a calculation will be made but does not show the result.

3. Distillation

Distillation separates compounds based on differences in their boiling points. The demonstration uses an ethanol–water mixture.

• Heat the mixture and observe the temperature and vapor condensing in the apparatus.
• The presenter reports a temperature near 80°C as ethanol begins to distill and drip into the receiver.
• The video notes that a temperature closer to ethanol’s boiling point indicates better separation, though it does not provide a final purity measurement.

4. Soxhlet Extraction

The presenter describes Soxhlet extraction as repeatedly washing a solid with a solvent to extract components.

• The apparatus shown includes a boiling flask, Soxhlet chamber, and condenser.
• Water is used as the solvent in the demonstration.
• Heating causes vapor to rise, condense, and drip onto the sample. The solvent then returns through the apparatus to the flask, allowing the extraction cycle to repeat.

5. Separating Funnel

A separating funnel is used to separate two immiscible liquid phases with different densities.

• The demonstration uses an iodine solution and cyclohexane, which form two visible layers.
• The funnel is stoppered, inverted, and mixed. It is also opened briefly to release pressure.
• The layers are separated by draining the lower phase through the stopcock while retaining the other phase in the funnel.

Speakers or Sources Featured

• One unnamed presenter/narrator, who explains and performs the demonstrations.
• Background music is heard; no additional speakers are identifiable.