Methods of separation

Question 1

Dissolving - ?

Answer 1

If a solid (the solute) is in contact with a liquid (the solvent), it gets bombarded by the particles of the liquid which are moving

Question 2

Dissolving - !

Answer 2

If the collisions are forceful enough, some of the particles of the solid will become dislodged from their fixed positions. They will then become suspended in amongst the liquid particles, and will move around with them

Question 3

Dissolving - ?!

Answer 3

This process can continue until all the particles of the solid have been separated from one another. As they are individually too small to be seen, the solid seems to have disappeared : it has of course DISSOLVED

Question 4

Chromatography - ◆

Answer 4

Draw a pencil baseline - because pencil is NOT soluble in water and so will not separate up the paper

Question 5

Chromatography - ◇

Answer 5

Measuring Rf value = distance travelled by dye / distance travelled by solvent

Question 6

Simple distillation - ?

Answer 6

Separates pure water from dissolved solids (solute)

Question 7

Simple distillation - !

Answer 7

When salt water is heated, only the water evaporates and turns into a gas and salt gets left behind. The water vapour cools and condenses and forms pure water in a condenser.

Question 8

Screening

Answer 8

Remove leaves + twigs

Question 9

Sedimentation

Answer 9

Small particles allowed to settle out

Question 10

Filtering

Answer 10

Filter beds of sand and gravel. Remove small insoluble particles

Question 11

Chlorination

Answer 11

Added in small quantities to kill microbes that could cause disease