Separation Techniques

Question 1

Chromatography

Answer 1

used to separate mixtures of coloured compounds e.g. inks, dyes, food colourings. They are separated based on their density – the lower the density, the further it travels up the paper.

Question 2

Magnetism

Answer 2

used to separate magnetic metals (e.g. iron) from non-magnetic substances.

Question 3

Crystallisation

Answer 3

Used to separate dissolved salts from their solvent. Heating the solution evaporates the solvent leaving the salt crystals.

Question 4

Separating funnel

Answer 4

used to separate immiscible liquids e.g. oil and water. Opening the tap on the funnel allows the less dense bottom layer to flow through. The tap can be closed when the top layer reaches the bottom.

Question 5

Filtration

Answer 5

used to separate insoluble solids from liquids. The solid residue is left in the filter paper as it cannot pass through and the liquid filtrate passes through.

Question 6

Simple distillation

Answer 6

used to separate miscible liquids based on their different boiling points. The liquid with the lower boiling point boils first and the gas passes down the condenser, cools and condenses again.

Question 7

Fractional distillation

Answer 7

used to separate miscible liquids based on their different boiling points. The liquids will evaporate and rise up the column. The liquid with the highest boiling point will condense on the beads and drip back down
whilst the liquid with the lowest boiling point will rise and pass into the condenser where it will cool and condense.