Materials:
- Calcium chloride dihydrate (CaCl2·2H2O)
- Distilled water
- Beakers or containers
- Filter paper
- Funnel
- Petri dish or watch glass
- Heat source (hot plate or stove)
Procedure:
1. Prepare a Saturated Solution:
- In a beaker, dissolve calcium chloride dihydrate in distilled water until no more salt can be dissolved. Stir or heat the solution gently to aid the dissolution process.
2. Filter the Solution:
- Filter the solution using filter paper and a funnel to remove any undissolved impurities or particles. This helps to obtain a clear filtrate.
3. Heat the Filtrate:
- Place the filtered solution in a beaker and heat it on a hot plate or stove. Continue heating until the solution starts to boil and reduce in volume. This step concentrates the calcium chloride solution.
4. Crystallization:
- As the solution continues to evaporate and becomes more concentrated, calcium chloride crystals will start to form. These crystals will appear on the sides of the beaker and at the bottom.
5. Cool the Solution:
- Remove the beaker from the heat source and let it cool down at room temperature or in a cool place. As the solution cools, more crystals will form.
6. Separate the Crystals:
- Once the solution has completely cooled, you will notice a layer of calcium chloride crystals at the bottom of the beaker.
Filter the cooled solution again using filter paper and a funnel. This step separates the crystals from the remaining liquid.
7. Wash the Crystals:
- Gently wash the collected crystals with a small amount of cold distilled water to remove any residual impurities.
8. Dry the Crystals:
- Transfer the washed crystals to a clean Petri dish or watch glass. Place them in a warm, dry place, or use a gentle stream of warm air to accelerate the drying process.
9. Store the Crystals:
- Once the crystals are completely dry, store them in a sealed container to prevent them from absorbing moisture from the air.
By following these steps, you can obtain pure crystals of calcium chloride. It's important to handle the chemicals and hot solutions with caution, and to wear appropriate safety gear, such as gloves and eye protection, during the process.
