Water — Paper 2 · IGCSE Science - Combined 0653

26 Which chemical test shows the presence of water? A Water has a boiling point of 100 °C. B Water has a freezing point of 0 °C. C Water turns anhydrous cobalt chloride from blue to pink. D Water turns anhydrous copper sulfate from blue to white.

1 marks

Answer: C

This question in 0653/22 Feb/March 2017

20 The diagram shows gas X burning and heating a liquid. Which row is correct? gas X A hydrogen v B hydrogen x Cc oxygen v D oxygen x liquid flame

1 marks

Answer: A

This question in 0653/23 Oct/Nov 2017

25 Why is drinking water treated with chlorine? A to improve the taste B to kill bacteria C to remove colour D to remove insoluble impurities

1 marks

Answer: B

This question in 0653/22 Feb/March 2018

24 A colourless liquid turns blue cobalt chloride paper to pink. The colourless liquid boils at 78 °C. Which statement about the colourless liquid is correct? A It does not contain water. B It is a hydrocarbon. C It contains some water. D It is pure water.

1 marks

Answer: C

This question in 0653/22 Feb/March 2019

15 Copper sulfate crystals dissolve in water. Which word describes the role of the water? A filtrate B solute C solution D solvent

1 marks

Answer: D

This question in 0653/21 May/June 2019

24 Which statement about water is not correct? A A water molecule consists of three atoms covalently bonded together. B The water supply is treated with chlorine to kill the bacteria in it. C Water changes the colour of cobalt chloride paper from blue to pink. D Water has a low melting point because covalent bonds are weak.

1 marks

Answer: D

This question in 0653/21 May/June 2019

24 Which statement about water is not correct? A A water molecule consists of three atoms covalently bonded together. B The water supply is treated with chlorine to kill the bacteria in it. C Water changes the colour of cobalt chloride paper from blue to pink. D Water has a low melting point because covalent bonds are weak.

1 marks

Answer: D

This question in 0653/22 May/June 2019

24 Which statement about water is not correct? A A water molecule consists of three atoms covalently bonded together. B The water supply is treated with chlorine to kill the bacteria in it. C Water changes the colour of cobalt chloride paper from blue to pink. D Water has a low melting point because covalent bonds are weak.

1 marks

Answer: D

This question in 0653/23 May/June 2019

24 Which statement about a chemical test for water is correct? A Anhydrous cobalt(II) chloride turns blue. B Anhydrous cobalt(II) chloride turns white. C Anhydrous copper(II) sulfate turns blue. D Anhydrous copper(II) sulfate turns white.

1 marks

Answer: C

This question in 0653/21 May/June 2022

24 Which colour change is seen when water is added to anhydrous cobalt(II) chloride? A blue to pink B blue to white C pink to blue D white to blue

1 marks

Answer: A

This question in 0653/22 May/June 2022

24 Which statement about the treatment of the water supply is correct? A After filtration and chlorination, the water contains no impurities. B Chlorine is added to remove dissolved impurities. C Water is filtered and chlorinated to remove solids and kill bacteria. D Water is filtered to remove dissolved impurities.

1 marks

Answer: C

This question in 0653/23 May/June 2022

24 Damp air is passed through a tube containing blue copper(II) sulfate and blue cobalt(II) chloride. damp air blue blue copper(II) sulfate cobalt(II) chloride What is observed? copper(II) sulfate cobalt(II) chloride A turns white turns pink B turns white no change C no change turns pink D no change no change

1 marks

Answer: C

This question in 0653/21 Oct/Nov 2022

15 Which statement about tap water is correct? A It is a compound. B It is a mixture of elements. C It is a pure substance. D It is a solution.

1 marks

Answer: D

This question in 0653/22 Oct/Nov 2023

25 Which processes are used in the treatment of the water supply? 1 chlorination 2 crystallisation 3 filtration 4 precipitation A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

1 marks

Answer: A

This question in 0653/22 Feb/March 2024

26 A water supply contains small insoluble impurities. It also contains bacteria. Which statement describes how the insoluble impurities are removed and how the bacteria are killed? A The water supply is filtered. B The water supply is filtered and treated with chloride ions. C The water supply is filtered and treated with chlorine. D The water supply is treated with chlorine and chloride ions.

1 marks

Answer: C

This question in 0653/21 May/June 2024

23 Which statement describes a chemical test for water? A Water boils at 100 °C. B Water turns blue cobalt(II) chloride pink. C Water turns blue copper(II) sulfate white. D Water turns red litmus paper blue.

1 marks

Answer: B

This question in 0653/22 Feb/March 2025

20 What is the reason for the treatment of the domestic water supply with chlorine? A to improve the taste B to kill microbes C to remove odours D to remove insoluble impurities

1 marks

Answer: B

This question in 0653/21 Oct/Nov 2025