9 (a) A sample of potable water contains impurities - Edexcel - GCSE Chemistry - Question 9 - 2021 - Paper 1
Question 9
9 (a) A sample of potable water contains impurities.
Why is this sample of water potable even though it contains impurities?
A The impurities have no smell
B Th... show full transcript
Worked Solution & Example Answer:9 (a) A sample of potable water contains impurities - Edexcel - GCSE Chemistry - Question 9 - 2021 - Paper 1
Step 1
Why is this sample of water potable even though it contains impurities?
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Answer
B The impurities are colourless.
Step 2
What is sedimentation?
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C The impurities in the waste water settle to the bottom of their container.
Step 3
State why the waste water is filtered.
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Answer
To remove any remaining solid impurities and to clarify the water.
Step 4
State the reason for chlorination.
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To kill harmful microorganisms and ensure the water is safe for drinking.
Step 5
Use the information about salt A and salt B in Figure 10 to evaluate this conclusion.
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Based on the data in Figure 10, adding 100 mg of salt B effectively removes a significant percentage of impurities from the waste water compared to salt A. This suggests that salt B is more efficient in purifying waste water, thereby justifying the conclusion.
Step 6
Devise a plan to separate pure water from this mixture, including a test to show that the water obtained is neutral.
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Set up a distillation apparatus using a round-bottom flask to heat the contaminated water.
As the water heats up, it will evaporate and travel through a condenser.
Collect the distilled water in a receiving flask.
To test for neutrality, use pH paper or litmus to ensure that the distilled water does not change color, indicating it is neutral.
