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9 Cards in this Set
- Front
- Back
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Which is better- soft water or hard water?
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Soft water :)
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What ions are in hard water, but not in soft water?
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In hard water there are magnesium and calcium ions.
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In general terms, what is the cause of scale and scum?
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Hard water- magnesium and calcium ions
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Why does scale appear?
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If you have hard water coming out your hot tap, this is bad.
When hard water is BOILED, some hardness is removed but the hardness STICKS to whatever it has been heated up in- and this is SCALE.. |
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Why does scum appear?
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Dissolved compounds in water (Mg and Ca) react with SOAP and form SCUM..
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How can we get rid of hard water?
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We could use an Ion exchange column, for some water.
Or we could add sodium carbonate. |
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How does an ion exchange column work?
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It exchanges calcium and magnesium ions for sodium ions.
There is then sodium ions in the water and Mg and Ca in the filter. To reuse the filter, it must be kept topped up with salt, so there are sodium ions in the filter again, and exchange can be done. |
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How does adding sodium carbonate (washing soda) do to hard water?
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It precipitates out the calcium and magnesium IONS, as an insoluble carbonate.
Diagram of floating bits on water- ~~¬~¬~~¬~~~¬~~~¬~~~¬~~~~~ |
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Why is an ion exchange column bad for drinking water?
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To drink water with added sodium is bad for your heart.
(remember, sodium chloride is salt) |
