Water from reservoirs is treated and tested before it is supplied to our homes - Edexcel - GCSE Chemistry - Question 1 - 2016 - Paper 1
Question 1
Water from reservoirs is treated and tested before it is supplied to our homes.
(a) Give a reason why water is tested before it is supplied to our homes.
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Worked Solution & Example Answer:Water from reservoirs is treated and tested before it is supplied to our homes - Edexcel - GCSE Chemistry - Question 1 - 2016 - Paper 1
Step 1
Give a reason why water is tested before it is supplied to our homes.
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Answer
Water is tested to ensure its purity, confirming that it is free from bacteria and does not cause illness. This ensures that the water is safe for drinking.
Step 2
Explain how you could show which sample was hard water and which sample was soft water.
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Answer
To determine which sample is hard water and which is soft water, mix each sample with soap. The hard water will form a scum or precipitate, indicating that it does not lather well with soap. In contrast, the soft water will form a lather, showing that it reacts well with soap.
Step 3
Which of these ions causes hardness in water?
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Answer
B magnesium ions
Step 4
Describe a test to show whether the hardness in a sample of water is temporary or permanent.
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Answer
To test whether the hardness is temporary, boil a sample of the water. If the water returns to being soft once boiled, it is temporary hard water. For permanent hardness, if there is no change after boiling, it indicates that the hardness is permanent.
Step 5
Complete the sentence by putting a cross (X) in the box next to your answer.
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