Water: past paper questions

Where the questions come from

• Question 17May/June 2026, paper 11Multiple choice1 mark

  Which statement about cobalt(II) chloride and copper(II) sulfate is correct?

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• Question 26Oct/Nov 2025, paper 11Multiple choice1 mark

  Which statement about water is correct?

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• Question 18Oct/Nov 2024, paper 12Multiple choice1 mark

  When a few drops of water are added to a solid, E, the colour changes from blue to pink. What is E?

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• Question 14Oct/Nov 2023, paper 11Multiple choice1 mark

  Solid S changes colour from white to blue when water is added. What is S?

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• Question 31May/June 2026, paper 11Multiple choice1 mark

  Why is distilled water used in practical chemistry rather than tap water?

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• Question 32Oct/Nov 2025, paper 12Multiple choice1 mark

  Some substances found in water from natural sources are potentially harmful. Which substance contains microbes that cause disease?

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• Question 32Oct/Nov 2024, paper 12Multiple choice1 mark

  Which substances in water from natural sources are beneficial to aquatic animals?

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• Question 28Oct/Nov 2023, paper 11Multiple choice1 mark

  Which test is used to show that a sample of water is pure?

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• Question 28May/June 2026, paper 12Multiple choice1 mark

  Water from natural sources may contain substances such as metal compounds, dissolved oxygen, phosphates and plastics. Which statement is correct?

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• Question 25Oct/Nov 2025, paper 13Multiple choice1 mark

  Four substances, or groups of substances, found in water from a natural source are listed.

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• Question 31Oct/Nov 2024, paper 13Multiple choice1 mark

  Which pollutants found in river water lead to deoxygenation?

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• Question 16Oct/Nov 2023, paper 12Multiple choice1 mark

  Which reaction shows a colour change from white to blue?

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• Question 18May/June 2026, paper 13Multiple choice1 mark

  Substance X is a blue solid. When X is heated, steam is produced and the solid turns white. What is X?

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• Question 26Oct/Nov 2025, paper 13Multiple choice1 mark

  Which element is used to remove tastes and odours in the treatment of the domestic water supply?

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• Question 3Oct/Nov 2024, paper 32Structured11 marksHas a diagram

  The list shows some substances present in water from natural sources. dissolved oxygen calcium compounds plastics harmful microbes State which one of these substances provides essential minerals for aquatic life.

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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 30May/June 2026, paper 13Multiple choice1 mark

  In a titration, why is distilled water and not tap water used to rinse the burette?

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• Question 30Oct/Nov 2025, paper 22Multiple choice1 mark

  Which flow chart describes the correct treatment sequence of the domestic water supply?

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• Question 3Oct/Nov 2024, paper 33Structured11 marksHas a diagram

  The list shows some gases in a sample of water. Choose from the list the gas that is essential for aquatic life. Draw a circle around your chosen answer.

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• Question 15Oct/Nov 2023, paper 13Multiple choice1 mark

  Anhydrous cobalt(II) chloride is blue and turns pink when water is added. How is this reaction reversed?

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• Question 28May/June 2026, paper 21Multiple choice1 mark

  Which test results show that a sample of water is pure?

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• Question 3Oct/Nov 2025, paper 31Structured9 marksHas a diagram

  Table 3.1 shows the masses of ions, in mg, present in a $1000{\text{ cm}}^3$ sample of river water. Table 3.1 Answer these questions using the information from Table 3.1. Name the positive ion that has the highest concentration.

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• Question 5Oct/Nov 2024, paper 33Structured11 marks

  Table 5.1 shows some properties of five halogens. Table 5.1 Use the information in Table 5.1 to predict: the melting point of astatine

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• Question 30Oct/Nov 2023, paper 13Multiple choice1 mark

  Some uses of water are listed. 1 for drinking 2 in chemical reactions 3 in swimming pools 4 in washing For which uses is it necessary to chlorinate the 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 3Oct/Nov 2025, paper 32Structured10 marksHas a diagram

  Table 3.1 shows the masses of ions, in mg, present in a $500{\text{ cm}}^3$ sample of contaminated water. Table 3.1 Answer these questions using the information from Table 3.1. Name the negative ion that has the highest concentration.

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• Question 16May/June 2024, paper 11Multiple choice1 markHas a diagram

  Water is added to anhydrous copper(II) sulfate. Which row describes the direction of energy change and the colour change of the mixture during the reaction?

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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 18May/June 2024, paper 12Multiple choice1 mark

  The equation for the hydration of anhydrous copper(II) sulfate is shown. $${\text{CuSO}}_4+5{\text{H}}_2\text{O}\to {\text{CuSO}}_4\cdot 5{\text{H}}_2\text{O}$$ Which colour change is observed in this reaction?

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• Question 7May/June 2026, paper 32Structured12 marksHas a diagram

  Natural water sources can be polluted by nitrates and some metal compounds. State one source of nitrates that pollute natural water sources.

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