Form 1:
Classification of substances

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Separation of immiscibles (Using a separating funnel)

Two or more liquids that form layers on mixing are immiscible. Immiscible mixture arrange themselves according to their densities

i.e. The denser liquid sink to the bottom. The less dense liquid floats on the denser one. Immicible mixtures can be separated from each other by using a separating funnel.

Experiment:

To separate an immiscible mixture of paraffin and water.

Procedure

Place about 100cm3 of water into a 250cm3 beaker.

Add about 100cm3 of paraffin into the beaker. Stir.

Transfer the mixture into a separating funnel.

Allow to settle for about one minute.

Open the tap, run out the lower layer out slowly into a clean beaker.

Close the tap when the upper layer is very close to the tap.

Run out the intermediate small amount of the mixture near the tap into a beaker.

Discard it.

Run out the remaining upper layer into a fresh beaker.

Place a portion of upper and lower layer into a watch glass separately after separating each. Ignite.

Observation

Water and paraffin are both colourless liquids.

Two layers are formed on mixing.

Colourless odorless liquid collected first. It does not catch fire.

A colourless liquid with characteristic smell collected later/second. It catches fire and burn with a yellow smoky flame.

Explanation

Water and paraffin are immiscible. Water is denser than paraffin.

When put in a separating funnel, paraffin float on water. On opening the tap, water runs out.

A mixture of water and paraffin at the junction of the two is discarded. It is not pure.

Set up of apparatus

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