Junior chemistry-separating mixtures(filtering sand and salt) (2024)

Separating mixtures
sand, salt and water

We can use the different properties of the components of amixture separate them. A mixture of sand, salt and water can be separated since all three substances have different properties. For example, sand is insoluble, while salt is soluble so therefore we can filter the sand and get the salty water. Since water turns to gas at 100^oC we can evaporate the water to obtain pure salt and pure water.

Lets see how.

Obtain some potting mix and place it in a 100ml beaker as shown on the right and add approximately 20 grams of salt.

We will need a 200ml beaker, distilled water bottle, funnel and filter paper.

Junior chemistry-separating mixtures(filtering sand and salt) (2)

Add 60mls of water and stir the mixture. Fold the filter paper as shown below.

Fold the filter paper so that it fits in the funnel.

Junior chemistry-separating mixtures(filtering sand and salt) (3)

Place the filter paper in the funnel and wet it with distilled water.

Pour the mixture into the filter paper.

The salt and water will pass through the filter paper while the large, undissolved pieces of sand will be trapped by the filter paper. The liquid that passes through the filter paper and is collected in the beaker is called the filtrate.

Why does the salt pass through the filter paper when it is dissolved in the water? Click to see a hint.

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