Separating Substances

Question 1

What does filtration separate?

Answer 1

An insoluble solute and a solvent

Question 2

What does crystallisation separate?

Answer 2

A soluble solute from a solvent

Question 3

What does simple distillation separate?

Answer 3

A soluble solute and a solvent
OR
Two liquids

Question 4

What does paper chromatography separate?

Answer 4

A mixture of soluble substances

Question 5

How would you calculate an Rf value?

Answer 5

Distance moved by solute (ink)
——————————————
Distance moved by solvent

Question 6

In paper chromatography, what is the stationary phase?

Answer 6

The chromatography paper

Question 7

In paper chromatography, what is the mobile phase?

Answer 7

The solvent

Question 8

In paper chromatography what does it mean if a spot stays on the pencil line?

Answer 8

The substance is insoluble in that solvent

Question 9

Why is a pencil used to draw the line in paper chromatography?

Answer 9

Because graphite is insoluble

Question 10

In paper chromatography what would you change if a spot stays on the pencil line?

Answer 10

The solvent

Question 11

In paper chromatography, how would you increase the accuracy of the Rf value?

Answer 11

Use a longer piece of paper

Question 12

What are the 3 stages of making water potable?

Answer 12

• Sedimentation
• Filtration
• Chlorination

Question 13

Describe simple distillation

Answer 13

• The solution is heated until it boils (it should have anti bumping granules in)
• The solvent vapour evaporates and travels up and along to the condenser
• When the vapour reaches the cold glass it condenses as a distillate

Question 14

Describe crystallisation

Answer 14

• The solution is heated to evaporate the solvent
• Cool and filter the liquid
• The solute is then left and crystals are formed