1G3 Separation Techniques

Which of the following methods can be used to obtain pure water from muddy soil?

• evaporation

• distillation

• filtration

• chromatography

Which result can be used to show the purity of a sample of water?

• It is colourless.

• It is odourless.

• It boils at a fixed temperature.

• It does not leave residue on filter paper.

Which factor is important for two substances to be separated by paper chromatography?

• Both must be liquid.

• Both must have different sizes.

• Both must have different colours.

• Both must have different solubilities in the same solvent.

Five different brands of chocolates were analysed using chromatography. The resulting chromatogram is shown.

Which of the chocolate brands 1, 2, 3, 4 or 5 is

(a) Pure? ​ (a)   ​ (b)  

(b) Mixture? ​ (c)   ​ (d)   ​ (e)  

• 1
• 4
• 2
• 3
• 5

The diagram shows an experimental set-up to obtain pure water from salt solution. 

Which of the following correctly represents the processes occurring at X and at Y?

• A

• B

• C

• D

On the diagram, label X or Y to determine the path of water in and out of the condenser.

Water In - ​ (a)  

Water Out - ​ (b)                                         

• Y
• X

Which real-life application does not involve the use of filtration?

• making coffee using coffee makers

• purifying water with sand and rocks

• separating tea leaves from tea

• trapping particles in the nose

The diagram shows two chromatograms that show the results obtained when an unknown substance was placed in water and ethanol respectively.

Based on the chromatograms, which statement is incorrect?

 

• The unknown substance boils at a fixed temperature.

• The unknown substance is an impure substance.

• The unknown substance is more soluble in ethanol than in water.

• The unknown substance is soluble in both water and ethanol.

Which of the following can be separated by magnetic attraction?

 

• iron and gold

• iron and nickel

• sand and sugar

• sand and water

Boiling chips are added into the distillation flask during distillation. 

What is the purpose of these boiling chips?

• to absorb excess heat

• to ensure smooth boiling

• to prevent liquid from boiling to dryness

• to remove impurities from the mixture