Form 1:
Classification of substances

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Solvent extraction

Solvent extraction is a method of separating oil from nuts/seeds.

Most nuts contain oil. First the nuts are crushed to reduce their size and increase the surface area.

A suitable volatile solvent is added. The mixture is filtered.

The filtrate solvent is then allowed to crystallize leaving the oil/fat. If a filter paper is rubbed/smeared with the oil/fat, it becomes translucent.

This is the test for the presence of oil/fat.

Experiment:

To extract oil from Macadamia nut seeds

Procedure

Crush Macadamia nut seeds form the hard outer cover .

Place the inner soft seed into a mortar.

Crush (add a little sand to assist in crushing).

Add a little propanone and continue crushing.

Continue crushing and adding a little propanone until there is more liquid mixture than the solid.

Decant/filter.

Put the filtrate into an evaporating dish.

Vapourize the solvent using solar energy /sunlight.

Smear/rub a portion of the residue left after evaporation on a clean dry filter paper.

Observation /Explanation

Propanone dissolve fat/oil in the macadamia nuts.

Propanone is more volatile (lower boiling point) than oil/fat. In sunlight/solar energy, propanone evaporate/vaporize leaving oil/fat(has a higher boiling point).

Any seed like corn, wheat , rice, soya bean may be used instead of macadamia seed. When oil/fat is rubbed/ smeared on an opaque paper, it becomes translucent.

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