Cristallisation Fractionnée du Sel et du Sable

Séparation d'un mélange par différences de solubilité

Crystallization Beginner (Middle School) 35 min ~$3,00

Objectif

Séparer un mélange de sel et de sable par cristallisation fractionnée, démontrant la dissolution, la filtration et la cristallisation par évaporation.

Contexte

This classic separation technique exploits the fact that salt dissolves in water while sand does not. The mixture is dissolved in hot water, filtered to remove sand, and then the salt is recovered by evaporation. This is fundamentally how salt has been harvested from seawater for millennia.

Avertissements de sécurité

  • Handle hot evaporating dish with tongs
  • Do not heat to dryness too rapidly — spattering risk

EPI requis

goggles

Matériaux

  • Salt-sand mixture (10 g)
    Pre-mixed approximately 50:50
  • Distilled water (100 mL)

Équipement

250 mL beaker Filter paper Funnel Evaporating dish Hot plate Stirring rod Analytical balance

Procédure

1

Weigh 10 g of the salt-sand mixture and record the mass.

2 min
2

Add the mixture to 100 mL of warm water in the beaker. Stir for 5 minutes to dissolve all the salt.

5 min
3

Filter the mixture through filter paper. The sand remains on the filter; the salt solution passes through.

5 min
4

Rinse the sand on the filter with a small amount of distilled water. Dry the sand and weigh it.

5 min
5

Pour the filtrate into the evaporating dish. Heat gently on the hot plate to evaporate the water.

12 min Remove from heat before completely dry
6

Once dry, weigh the recovered salt. Calculate the percentage of each component.

3 min
7

Compare the total recovered mass with the initial mass. Calculate percent recovery.

3 min

Résultats attendus

The total mass of recovered salt + sand should be close to the original 10 g (typically 90-98% recovery). Some loss occurs during transfer and on filter paper. The separated components should be visually distinct.

Nettoyage

Salt solution can go down the drain. Sand can go in the trash. Rinse all glassware.

Détails

Catégorie
Crystallization
Difficulté
Beginner (Middle School)
Durée
35 min
Coût estimé
$3,00
Étapes
7
Matériaux
2

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Frequently Asked Questions

What is the objective of Cristallisation Fractionnée du Sel et du Sable?
Séparer un mélange de sel et de sable par cristallisation fractionnée, démontrant la dissolution, la filtration et la cristallisation par évaporation.
How difficult is Cristallisation Fractionnée du Sel et du Sable?
This experiment is rated as Beginner (Middle School). It takes approximately 35 minutes to complete.
What safety precautions are needed for Cristallisation Fractionnée du Sel et du Sable?
Key safety precautions include: Handle hot evaporating dish with tongs; Do not heat to dryness too rapidly — spattering risk.
What materials are needed for Cristallisation Fractionnée du Sel et du Sable?
The main materials required are: Salt-sand mixture, Distilled water.
What results should I expect from Cristallisation Fractionnée du Sel et du Sable?
The total mass of recovered salt + sand should be close to the original 10 g (typically 90-98% recovery). Some loss occurs during transfer and on filter paper. The separated components should be visually distinct.