Flashcards
Water
Flashcards do conjunto (11)
- 1How is water purified1) Sedimentation-
Water is stored in settling tanks, larger particles sink to the bottom and water is drawn off leaving it behind
2) Filtration-
Water is passed through a system of filters to remove small particles
3) Chlorination-
Chlorine is added to kill the bacteria - 2Name 4 reasons why we need water1) Drinking
2) Hygiene (washing)
3) Coolants in factories (e.g. electrolysis)
4) Farming-to water crops - 3Name 4 ways we can conserve water1) Fix leaking pipes
2) 'Half flush' button on toilets
3) Shower instead of bath
4) Turn off taps - 4Describe hard water (2)1) Contains dissolved calcium and magnesium ions
2) Can be temporary or permanent - 5Describe temporary hard water (2)1) Contains calcium and magnesium hydrogen carbonates
2) Can be removed by boiling - 6Describe permanent hard water (2)1) Contains magnesium and calcium sulphates or chlorides
2) Can be removed by adding sodium carbonate or with an ion exchange column - 7Describe the 2 ways of removing permanent hardness1) Add sodium carbonate (washing soda)
-Sodium carbonate precipitates the calcium ions as calcium carbonate
-Sodium Carbonate + Calcium Sulphate
---->
Sodium Sulphate + Calcium Carbonate
2) Ion exchange column
-Resin in the column replaces calcium ions with sodium ions (which don't cause hardness) The resin needs to be replaced now and again - 8Describe a method of testing for hardness and the results of the test1) Add the same amount of water into two test tubes
2) Add the same amount of soap to each test tube
3) Shake both for 30 seconds
4) With a ruler measure the amount of lather
RESULT
-Soft water will form a lather
-Hard water will form a scum
*A small amount of soap forms a large lather in soft water
*A large amount of soap forms a small lather in hard water - 9Name 3 advantages of hard water1) It tastes better
2) Contains minerals needed in your diet e.g. magnesium and calcium
3) Magnesium ions give protection against heart disease - 10Name 3 disadvantages of hard water1) Temporary hardness can produce a scale which clogs water pipes, kettle elements and boilers
2) It needs more soap to lather (more expensive) - 11Describe soft waterWater that contains few or no calcium or magnesium ions
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- Descrição
- GCSE Chemistry FlashCards sobre Water, criado por leahduckett1999 em 19-03-2016.
- Criado por
- leahduckett1999
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