filtration, crystallisation, distillation

Question 1

Filtration is used

Answer 1

for an insoluble solid and a solvent

Question 2

In order to do filtration, you would need…

Answer 2

a funnel, a test tube and filter paper

Question 3

In filtration, the filtered solid is called

Answer 3

a RESIDUE

Question 4

In filtration, the solvent is called

Answer 4

a FILTRATE

Question 5

Explain the process of filtration

Answer 5

• Add filter paper to a filter funnel
• add your solution of an insoluble solid and a solvent
• the solvent will be able to drip through the tiny holes in the filter paper but the solid will not
• the solid will be left in the funnel - the residue
• the solvent will drip to the test tube - the filtrate

Question 6

Crystallisation is used for…

Answer 6

to separate a soluble solid from a mixture

Question 7

the process of crystallisation is…

Answer 7

• Pour the solution into an evaporating dish and heat the solution - the water will evaporate and the solution will become more concentrated
• When crystals have started to form (the point of crystallisation) or when the water has evaporated, remove the dish from the bunsen
• allow to cool
• the salt will begin to form crystals as it becomes insoluble
• filter the crystals and then leave them in a warm place to dry

Question 8

What is the difference between simple distillation and fractional distillation?

Answer 8

Simple distillation is used for mixtures with substances that have very different boiling points whereas fractional distillation is used for substances that have very close boiling points

Question 9

When is distillation used?

Answer 9

Distillation is used to separate out mixtures that contain liquids

Question 10

In distillation, what piece of equipment makes the gas turn back into a liquid?

Answer 10

the condenser

Question 11

In distillation, what has different temperatures for the substances to evaporate at?

Answer 11

fractionating column

Question 12

Explain the process of simple distillation

Answer 12

• the solution is heated until the substance with the lowest boiling point evaporates
• the vapour cools and condenses, and the liquid form is collected
• the rest of the solution remains in the flask

Question 13

Explain the process of fractional distillation

Answer 13

• the mixture is in a flask with a fractionating column on top
• the liquid with the lowest boiling point evaporates first
• the column has a heat gradient - the top of the fractionating column is cooler than the bottom, so when the thermometer matches the boiling point of this liquid, the substance will have reached the top of the column
• Liquids with the higher boiling point may try to evaporate but they will condense before reaching the top
• when substance one has collected, increase the temperature until the next substance reaches the top of the fractionating column

Question 14

Fractional distillation is usually used in real life for

Answer 14

crude oil