Separation and purification — Paper 2 · IGCSE Sciences - Co-ordinated (Double) 0654

20 The equation for the reaction between aqueous calcium chloride and aqueous potassium sulfate is shown. CaCl 2(aq) + K2SO4(aq) → CaSO4(s) + 2KCl (aq) Which process is not used to produce the pure salt calcium sulfate? A crystallisation of the salt from solution B filtration to collect the salt C mixing two soluble salts together D washing the salt with cold water

1 marks

Answer: A

This question in 0654/23 May/June 2017

26 Which statement about the products of the fractional distillation of petroleum is not correct? A Fractions obtained from high up the fractional distillation column contain small molecules. B Fractions obtained from low down the fractional distillation column have low boiling points. C Large molecules have large intermolecular attractive forces. D Refinery gas is used for cooking and heating.

1 marks

Answer: B

This question in 0654/23 May/June 2017

15 Which statement about fractional distillation is correct? A A chemical change occurs because new substances are formed. B A chemical change occurs because no new substances are formed. C A physical change occurs because new substances are formed. D A physical change occurs because no new substances are formed.

1 marks

Answer: D

This question in 0654/22 Oct/Nov 2017

15 Hexane and octane are liquid hydrocarbons that mix together. Which apparatus is used to separate a mixture of these two liquids? A B C D xxxxxxxxx heat xxxxxxxxx heat

1 marks

Answer: D

This question in 0654/21 Oct/Nov 2018

15 Hexane and octane are liquid hydrocarbons that mix together. Which apparatus is used to separate a mixture of these two liquids? A B C D xxxxxxxxx heat xxxxxxxxx heat

1 marks

Answer: D

This question in 0654/22 Oct/Nov 2018

15 Hexane and octane are liquid hydrocarbons that mix together. Which apparatus is used to separate a mixture of these two liquids? A B C D xxxxxxxxx heat xxxxxxxxx heat

1 marks

Answer: D

This question in 0654/23 Oct/Nov 2018

20 Hydrochloric acid and sodium hydroxide neutralise each other to form water and sodium chloride. Which method is used to make the solution crystallise? A chromatography B evaporation C filtration D fractional distillation

1 marks

Answer: B

This question in 0654/21 May/June 2019

21 Hydrochloric acid and sodium hydroxide neutralise each other to form water and sodium chloride. Which method is used to make the solution crystallise? A chromatography B evaporation C filtration D fractional distillation

1 marks

Answer: B

This question in 0654/22 May/June 2019

23 Hydrochloric acid and sodium hydroxide neutralise each other to form water and sodium chloride. Which method is used to make the solution crystallise? A chromatography B evaporation C filtration D fractional distillation

1 marks

Answer: B

This question in 0654/23 May/June 2019

21 Copper sulfate is made by adding an excess of copper carbonate to dilute sulfuric acid and stirring. The excess solid is removed. Most of the water is then removed. The solution is left for solid copper sulfate to form. In which order is apparatus used? A Bunsen burner, tripod and flask  filter funnel  crystallising dish B Bunsen burner, tripod and flask  crystallising dish  filter funnel C filter funnel  crystallising dish  Bunsen burner, tripod and flask D filter funnel  Bunsen burner, tripod and flask  crystallising dish

1 marks

Answer: D

This question in 0654/21 May/June 2020

26 The diagram represents the fractional distillation of petroleum. Four fractions, W, X, Y and Z, are produced. W X Y Z petroleum Which statement about fraction Y is correct? A The forces of attraction between molecules in Y are smaller than those in W. B The molecules in Y are smaller than the molecules in Z. C Y has a lower boiling point than X. D Y vapourises more readily at room temperature than W and X, but less readily than Z.

1 marks

Answer: B

This question in 0654/22 May/June 2020

14 A sample of water is contaminated with insoluble chalk and a soluble salt. Which two processes are used to separate the water from the chalk and salt? A distillation and chromatography B distillation and crystallisation C filtration and chromatography D filtration and crystallisation

1 marks

Answer: D

This question in 0654/21 Oct/Nov 2020

14 An aqueous salt solution contains an insoluble impurity. Which processes are used to obtain pure salt crystals? A distil then crystallise B distil then chromatography C filter then crystallise D filter then chromatography

1 marks

Answer: C

This question in 0654/22 Oct/Nov 2020

14 A mixture of solid sulfur and solid sodium chloride is added to water and stirred. Sulfur is insoluble in water. Sodium chloride is soluble in water. Which processes are used to obtain pure sodium chloride from the mixture? A distillation then chromatography B distillation then crystallisation C filtration then chromatography D filtration then crystallisation

1 marks

Answer: B

This question in 0654/23 Oct/Nov 2020

15 Pure substance X has a melting point of 110 C. The melting point ranges of four impure samples of substance X are measured. What is the melting point range of the most impure sample of substance X? melting point / C A 81–85 B 86–92 C 98–99 D 102–110

1 marks

Answer: A

This question in 0654/21 May/June 2021

15 Which method can be used to separate graphite from dilute nitric acid? A chromatography B crystallisation C distillation D filtration

1 marks

Answer: D

This question in 0654/22 May/June 2021

14 A mixture contains solid P dissolved in liquid Q. Which process is used to obtain a pure sample of liquid Q from this mixture? A crystallisation B distillation C evaporation D paper chromatography

1 marks

Answer: B

This question in 0654/21 May/June 2022

14 Information about the solubility in water of some calcium compounds is listed.  Calcium hydroxide is soluble.  Calcium carbonate is insoluble.  Calcium chloride is soluble. Which method is used to prepare pure calcium chloride? A Add excess calcium hydroxide to dilute hydrochloric acid, filter, then crystallise. B Add excess calcium carbonate to dilute hydrochloric acid, filter, then crystallise. C Add excess dilute hydrochloric acid to calcium hydroxide, filter, then crystallise. D Add excess dilute hydrochloric acid to calcium carbonate, filter, then crystallise.

1 marks

Answer: B

This question in 0654/23 May/June 2022

26 Petroleum is a mixture of hydrocarbons which is separated into fractions by fractional distillation. Which statements describe the fraction collected at the bottom of the fractionating column? 1 It contains the smallest molecules. 2 It has the weakest forces between molecules. 3 It is the most viscous. 4 It is the least flammable. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

1 marks

Answer: D

This question in 0654/23 May/June 2022

14 A student adds excess copper oxide powder to warm dilute sulfuric acid. Aqueous copper sulfate is formed. Which method is used to remove the unreacted copper oxide? A chromatography B crystallisation C distillation D filtration

1 marks

Answer: D

This question in 0654/22 Feb/March 2023

14 An aqueous salt solution contains an insoluble impurity. Which processes are used to obtain pure salt crystals? A distillation then crystallisation B distillation then chromatography C filtration then crystallisation D filtration then chromatography

1 marks

Answer: C

This question in 0654/21 May/June 2023

26 Petroleum is separated into fractions by fractional distillation. Information about uses of some fractions and positions in the fractionating column where they are collected is shown. fraction use position 1 gasoline making roads below refinery gas 2 bitumen petrol for car engines bottom of column 3 naphtha making chemicals below gasoline 4 refinery gas heating and cooking top of column Which rows are correct? A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

1 marks

Answer: D

This question in 0654/21 May/June 2023

14 Hexane and octane are liquid hydrocarbons that mix together. Which apparatus is used to separate a mixture of these two liquids? A B C D xxxxxxxxx heat xxxxxxxxx heat

1 marks

Answer: D

This question in 0654/22 May/June 2023

20 Copper(II) sulfate is produced by reacting copper(II) oxide with dilute sulfuric acid. The stages in the process to produce pure dry crystals are listed. 1 Leave to crystallise in a cool place. 2 Filter the reaction mixture. 3 Press the crystals between dry filter papers. 4 Add copper(II) oxide until it is in excess. 5 Heat the filtrate to concentrate it. 6 Heat the dilute sulfuric acid. What is the correct order for these stages? A 6  4  2  5  3  1 B 6  4  1  2  5  3 C 6  4  2  5  1  3 D 4  6  2  1  5  3

1 marks

Answer: C

This question in 0654/22 May/June 2023

14 A mixture of solid sulfur and solid sodium chloride is added to water and stirred. Sulfur is insoluble in water. Sodium chloride is soluble in water. Which processes are used to obtain pure sodium chloride from the mixture? A distillation then chromatography B distillation then crystallisation C filtration then chromatography D filtration then crystallisation

1 marks

Answer: D

This question in 0654/23 May/June 2023

14 A sample of water contains two useful substances, insoluble chalk and a soluble salt. Which two processes are used to individually separate the insoluble chalk from the soluble salt and from the water? A distillation and chromatography B distillation and crystallisation C filtration and chromatography D filtration and crystallisation

1 marks

Answer: D

This question in 0654/22 Oct/Nov 2023

14 Which process is used to obtain water from a salt solution? A chromatography B crystallisation C distillation D filtration

1 marks

Answer: C

This question in 0654/23 May/June 2024

14 Sea water is heated in the apparatus shown. Y cold water in sea water X water out heat Which row describes changes at positions X and Y? at X at Y A concentration of solution decreases solvent condenses B concentration of solution decreases solute condenses C concentration of solution increases solvent condenses D concentration of solution increases solute condenses

1 marks

Answer: C

This question in 0654/21 Oct/Nov 2024

24 A student prepares an insoluble salt by neutralising an acid with an alkali. Which method is used to separate the salt from the reaction mixture? A chromatography B distillation C evaporation D filtration

1 marks

Answer: D

This question in 0654/22 May/June 2025

24 Which two processes are used to treat the domestic water supply? A chlorination and evaporation B chlorination and filtration C crystallisation and evaporation D crystallisation and filtration

1 marks

Answer: B

This question in 0654/23 May/June 2025

23 Gasoline and diesel oil are fractions obtained by the fractional distillation of petroleum. Which row about gasoline and diesel oil is correct? temperature at which size of molecules the fraction is collected in the fraction A gasoline higher than diesel oil gasoline larger than diesel oil B gasoline higher than diesel oil gasoline smaller than diesel oil C diesel oil higher than gasoline diesel oil larger than gasoline D diesel oil higher than gasoline diesel oil smaller than gasoline

1 marks

Answer: C

This question in 0654/21 Oct/Nov 2025

23 Which row explains why filtration and chlorination are used in the treatment of the domestic water supply? filtration chlorination A to remove soluble substances to kill microbes B to remove insoluble substances to kill microbes C to kill microbes to remove insoluble substances D to remove insoluble substances to remove soluble substances

1 marks

Answer: B

This question in 0654/23 Oct/Nov 2025