Separation and purification: past paper questions

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• Question 38May/June 2026, paper 12Multiple choice1 mark

  Which processes are required to separate sand from a mixture of solid sodium chloride and sand?

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• Question 23Oct/Nov 2024, paper 12Multiple choice1 mark

  The following steps are done to prepare solid magnesium sulfate.

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• Question 18Oct/Nov 2023, paper 11Multiple choice1 mark

  Copper(II) sulfate is formed by reacting excess solid copper(II) carbonate with dilute sulfuric acid. Which processes are part of the preparation of solid copper(II) sulfate?

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• Question 38Oct/Nov 2025, paper 11Multiple choice1 markHas a diagram

  The apparatus used to separate a mixture is shown. What is the mixture?

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• Question 37Oct/Nov 2024, paper 12Multiple choice1 markHas a diagram

  Four different organic compounds are separated by a fractionating column. The table shows the boiling points of the compounds.

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• Question 39Oct/Nov 2023, paper 11Multiple choice1 mark

  The equation for the reaction of aqueous calcium nitrate and aqueous sodium hydroxide is shown.

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• Question 21Oct/Nov 2025, paper 12Multiple choice1 mark

  Which mixture of solids is separated by adding water, stirring, and then using filtration?

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• Question 40Oct/Nov 2024, paper 12Multiple choice1 markHas a diagram

  Sample M contains calcium carbonate and sodium nitrate. The result of adding water to M, stirring and filtering is shown. No chemical reaction occurs.

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• Question 31Oct/Nov 2023, paper 12Multiple choice1 markHas a diagram

  The flow chart shows stages in the treatment of river water to produce drinking water.

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• Question 39May/June 2026, paper 22Multiple choice1 mark

  Which process is used to produce drinking water from sea water?

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• Question 40Oct/Nov 2025, paper 21Multiple choice1 mark

  Ethanol can be made by fermentation of sugar, using yeast. This produces a mixture of ethanol and water. How is ethanol separated from this mixture?

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• Question 33Oct/Nov 2023, paper 12Multiple choice1 mark

  What are the main substances produced by the fractional distillation of liquid air?

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• Question 3May/June 2026, paper 42Structured15 marks

  The salt zinc sulfate is prepared by adding excess solid zinc carbonate to dilute sulfuric acid. Complete the equation for this reaction.

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• Question 11Oct/Nov 2025, paper 23Multiple choice1 mark

  Which statement describes a saturated solution?

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• Question 19Oct/Nov 2024, paper 21Multiple choice1 markHas a diagram

  Copper(II) sulfate is made when copper(II) carbonate reacts with dilute sulfuric acid. $${\text{CuCO}}_3+{\text{H}}_2{\text{SO}}_4\to {\text{CuSO}}_4+{\text{H}}_2\text{O}+{\text{CO}}_2$$ Pure copper(II) sulfate crystals are obtained.

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• Question 39Oct/Nov 2023, paper 12Multiple choice1 markHas a diagram

  The apparatus shown is used to separate a mixture. What is the mixture?

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• Question 1May/June 2026, paper 61Structured8 marksHas a diagram

  A student tries to make crystals of hydrated copper(II) sulfate, ${\mathrm{C}\mathrm{u}\mathrm{S}\mathrm{O}}_4\cdot 5{\mathrm{H}}_2\mathrm{O}$. Crystals of hydrated copper(II) sulfate are blue. The student makes aqueous copper(II) sulfate by reacting copper(II) carbonate with dilute sulfuric acid.

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• Question 3Oct/Nov 2025, paper 33Structured10 marks

  Table 3.1 shows the masses of ions, in $\mathrm{m}\mathrm{g}$, present in a $600{\mathrm{c}\mathrm{m}}^3$ sample of contaminated water.

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• Question 39Oct/Nov 2024, paper 21Multiple choice1 markHas a diagram

  Which row shows how the boiling point and the melting point of water change when a soluble impurity is added to the water?

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• Question 1May/June 2026, paper 62Structured8 marksHas a diagram

  Alkanes are flammable hydrocarbons. Table 1.1 gives the boiling points of three alkanes.

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• Question 3Oct/Nov 2025, paper 42Structured13 marks

  A student prepares a sample of the insoluble salt barium sulfate, ${\text{BaSO}}_4$. The student adds aqueous sodium sulfate, ${\text{Na}}_2{\text{SO}}_4(\text{aq})$, to aqueous barium chloride, ${\text{BaCl}}_2(\text{aq})$. The student carries out the following steps.

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• Question 39Oct/Nov 2024, paper 22Multiple choice1 mark

  Pure solid copper(II) nitrate can be obtained from a mixture of copper(II) nitrate and copper powder. Three stages in the method are listed.

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• Question 5Oct/Nov 2025, paper 43Structured12 marks

  This question is about metallic compounds. Insoluble metal salts, such as lead(II) sulfate, are made by precipitation. When aqueous lead(II) ions react with aqueous sulfate ions, a precipitate of lead(II) sulfate forms.

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• Question 39Oct/Nov 2024, paper 23Multiple choice1 mark

  Some information about solid silver chloride and solid sodium chloride is shown.

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• Question 2Oct/Nov 2023, paper 31Structured6 marksHas a diagram

  Fig. 2.1 shows the distillation apparatus that can be used to separate water from aqueous copper(II) sulfate. Explain how distillation separates water from aqueous copper(II) sulfate.

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• Question 1Oct/Nov 2025, paper 62Structured9 marksHas a diagram

  Eggshells are made from a mixture of calcium carbonate and other insoluble substances. Calcium carbonate reacts with dilute hydrochloric acid. The equation for the reaction is shown.

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• Question 3Oct/Nov 2024, paper 41Structured18 marks

  Copper(II) sulfate has the formula ${\mathrm{C}\mathrm{u}\mathrm{S}\mathrm{O}}_4$. Aqueous copper(II) sulfate is a blue solution. A sample of aqueous copper(II) sulfate is made by adding excess copper(II) oxide, $\mathrm{C}\mathrm{u}\mathrm{O}$, to hot dilute sulfuric acid, ${\mathrm{H}}_2{\mathrm{S}\mathrm{O}}_4$.

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• Question 4Oct/Nov 2025, paper 63Essay6 marks

  Duralumin is an alloy containing a mixture of the metals aluminium, copper, magnesium and manganese only. Table 4.1 gives some information about the four metals in duralumin. Table 4.1 Plan an investigation to find the percentage by mass of aluminium in a sample of duralumin.

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• Question 1Oct/Nov 2024, paper 61Structured5 marksHas a diagram

  A student has a mixture of copper(II) carbonate powder and crystals of sodium sulfate. Copper(II) carbonate is insoluble in water. Sodium sulfate is soluble in water.

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• Question 39May/June 2025, paper 11Multiple choice1 mark

  Excess solid magnesium oxide is added to dilute nitric acid. Which separation technique is used to remove the excess solid magnesium oxide after the reaction finishes?

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