Filtration

If a substance can dissolve in a particular solvent, is it soluble.

Substances can be soluble in one solvent, but insoluble in another.

e.g. Nail varnish is soluble in nail varnish remover, but not in water.

When we filter, we use a porous surface that allows the smaller particles to pass through while the larger ones don't.

Porous - having holes (pores) that allow smaller particles to pass through.

When we are performing filtration in the lab, we have specific equipment we use.

Draw and label the diagram

1) Pour the solution of liquid and insoluble solid into the funnel with the filter paper - slowly.

2) Allow the liquid to drip through the filter paper, leaving the insoluble solid (the residue) on the filter paper.

The liquid collected is called the filtrate

Filter paper comes in different grades, with smaller holes for trapping smaller particles.

We can also 'flute' it to increase surface area. Why would this be useful?

In your books, draw a particle diagram of a mixture of salt and water

You only need to draw what should be in the empty box

If we evaporate the water from the solution, the salt will remain in the dish. We can do it slowly over time as evaporation will occur by itself, or we can use heat to speed it up.

Draw this diagram in your books

This is used to produce solid crystals from a solution.

How could we obtain the salt from a mixture of sand and salt?