C3, Hard and soft water

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  • Created by: emmajane_
  • Created on: 12-04-14 11:13
What determines if water is hard or soft?
The amount of mineral ions dissolved in the water
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What type of mineral ions does hard water contain? What do they form?
Dissolved compounds such as magnesium and calcium and they form scum
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What does soft water form that hard water doesn't?
Forms lather from soap
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What do you ahve to perform to find out if water is hard or soft?
Titrations
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Name step one of titration
Put a known volume of water in a conical flask
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Name step two of titration
Add soap solution with a burette
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Name steps three and four of titration
3. Mixture swirled to form a lather 4. Harder the water- the more soap solution needed
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How can yoif water is temporarily hard and what does it contain?
It softenes at boiling point and contains hydrogen carbonate ions. These decompose at boiling point
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How can you tell if water is permenantly hard and which ions does it contain?
Stays hard at boiling point and contains sulphate ions that don't decompose at boiling point
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Name 3 benefits of hard water
1. Tastes better 2. Helps reduce heart disease 3. Good for bones and teeth
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Name 2 dissadvantages of hard water
1. More soap needed to produce lather- higher coss 2. Scum produce which looks bad
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Name a drawback of temporary hard water
Reduces efficiency of appliances because it creates limescale blocking pipes
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How do you soften hard water?
Remove sodium ions
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How do you remove sodium ions from water?
Using exchange columns
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Why does adding sodium carbonate (washing powder) to hard water soften it?
Thr carbonate ions react with calcium and magnesium ions, producing an insoluble precipitate. This produces limescale
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Other cards in this set

Card 2

Front

What type of mineral ions does hard water contain? What do they form?

Back

Dissolved compounds such as magnesium and calcium and they form scum

Card 3

Front

What does soft water form that hard water doesn't?

Back

Preview of the front of card 3

Card 4

Front

What do you ahve to perform to find out if water is hard or soft?

Back

Preview of the front of card 4

Card 5

Front

Name step one of titration

Back

Preview of the front of card 5
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