Separating Mixtures, Study notes of Chemistry

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Separating

Mixtures

Many of the substances we use everyday were actually once part of a mixture. Someone somewhere separated that substance from the mixture so we could use it.

Separating substances from mixtures is an important part of chemistry and modern industry.

Here, a sieve is used to separate a mixture of sand and gravel.

The sieve has very small holes. Coarse particles of sand are separated or broken up by grinding against one-another and the screen openings.

Filtering

A mixture of water and an insoluble (cannot be dissolved) substance like sand can be separated by filtering.

What is a filter?

Any substance, as cloth, paper, through which liquid or gas is passed to remove solids.

Evaporating

By dissolving salt in water we make a solution. The salt disappears into the water.

We can separate

the salt from the

water by boiling

the solution.

The water will

evaporate until it is

all gone. The salt

will be left behind. If we collect the water vapor

that evaporates we can cool it to form water again.