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Water that is safe to drink is called potable water - AQA - GCSE Chemistry Combined Science - Question 2 - 2022 - Paper 2
Question 2
Water that is safe to drink is called potable water. Compare how easily potable water can be obtained from: • waste water (sewage) • ground water (fresh water). [... show full transcript
Worked Solution & Example Answer:Water that is safe to drink is called potable water - AQA - GCSE Chemistry Combined Science - Question 2 - 2022 - Paper 2
Step 1
Compare how easily potable water can be obtained from waste water (sewage) and ground water (fresh water).
Answer
Potable water from ground water is easier to obtain compared to waste water. This is due to the following reasons:
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Simplicity of Process: Ground water typically requires fewer processes than waste water, which often involves treatment steps to remove contaminants.
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Time Efficiency: Extracting potable water from ground water takes less time compared to processing waste water, which may involve various purification stages.
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Filtration Methods: Ground water is commonly filtered through sediment filters, whereas waste water requires additional methods like screening and sedimentation to remove solid waste.
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Sterilization Requirements: While both sources need sterilization (usually using chlorine or UV light to eliminate bacteria), the treatment for waste water is generally more complex due to its higher contamination levels.
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Organic Matter Removal: Waste water requires aerobic biological treatment to remove organic matter, which is not a requirement for ground water extraction.
Step 2
Step 3
Calculate the concentration of sodium chloride in grams per dm³.
Answer
To find the concentration of sodium chloride in grams per dm³ from the given 2.40 g in 150 cm³ of salty water, use the formula:
ext{Concentration} = rac{ ext{mass}}{ ext{volume}}
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Convert 150 cm³ to dm³:
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Then, calculate the concentration: ext{Concentration} = rac{2.40 ext{ g}}{0.15 ext{ dm}^3}
Thus, the concentration of sodium chloride is 16 g/dm³.