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Chemistry revision

Hard and Soft water

What two main compounds are found in hard water? Magnesium and Calcium.
What is temporary hardness? The property of hard water that can be removed by boiling the water.
What is permanent hardness? The property of hard water that cannot be removed by boiling the water.
What is the problem with hard water? Hard water wastes soap by producing scum that must be rinsed off.
How do you 'soften' permanently hard water? By using an ion exchange column.
What is an ion exchange column? A device used to soften hard water. Contains a resin with an excess of Sodium (Na+)ions. When the water passes through the column the Calcium (Ca2+) ions are exchanged for Sodium ions
Why does ion exchange soften all types of water, while boiling on removes temporary hardness. Because an ion exchange swaps Calcium ions with Sodium ions, meaning the Calcium ions aren't there anymore. The water is no longer hard.
Created by: elisa1011



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