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This question is about water - AQA - GCSE Chemistry - Question 4 - 2016 - Paper 3
Question 4
This question is about water. Hard water contains dissolved compounds. Explain one benefit of drinking hard water. What is the name of the solid formed when hard w... show full transcript
Worked Solution & Example Answer:This question is about water - AQA - GCSE Chemistry - Question 4 - 2016 - Paper 3
Step 1
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Step 3
Describe how using temporary hard water in an electric kettle reduces the efficiency of the kettle.
Answer
Temporary hard water contains dissolved calcium hydrogen carbonate ions. When heated or boiled in the kettle, these ions decompose and form calcium carbonate, leading to the formation of a precipitate or scale. This scale coats the heating element and restricts heat transfer to the water, thereby reducing the kettle's efficiency.
Step 4
Explain how an ion exchange resin changes the dissolved compounds in tap water to improve the water.
Answer
Ion exchange resins used in water filters typically contain sodium or hydrogen ions. These resins work by replacing calcium and magnesium ions present in hard water. As the water flows through the resin, the calcium and magnesium ions are displaced and removed, resulting in softened water. This process enhances water quality by mitigating hardness and preventing scale buildup.