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GCSE CHemistry 3
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use equations to explain how pure water can become temporary hard water and how this change got rid of
There are two types of distillation That can be used to obtain pure water
Solar distillation And flash distillation
Where/when can solar distillation be used
On desert coastlines to obtain drinking water from the sea
it could be used on stranded boats to obtain drinking water from the sea
it could be used iI underdeveloped countries to obtain drinking water from water contaminated by microorganisms
how does flash distillation work
Heats the water under pressure then fast evaporation occurs
What are sac advantages of flash distillation
We can obtain drinking water from the sea
What are the disadvantages of flash distillation
It uses fossil fuels which Releases Carbon dioxide into the atmosphere so there is an increased contribution towards global warming
it produces a concentrated salt solution which must be disposed of carefully or it could seriously damage the ecology of the sea
What are the advantages of having fluoride ions
in drinking water
healthier teeth
reduces NHS bills
What are the disadvantages of having fluoride ions in drinking water
Can cause bone weakening
tooth Mottling
What is the equation for the addition of chlorine to water
Cl2 + H2O --> OCl- + 2H+ + 2Cl-
the OCl- is hyper-chlorite which kills bacteria
There are two types of water filters
Activated charcoal - which has a high surface areas with a slight + chArge
microscopic silver particles - this kills microorganisms that grow in filters
What are the advantages of having chlorine in water
Kills bacteria
What are the disadvantages of having chlorine in water
Taste
too much can be toxic
What are the advantages of ion exchange
Gets rid of temporary and permanent hardness
What are the disadvantages of ion exchange
magnesium and calcium ions are swapped for sodium and hydrogen ions
magnesium and calcium ions are good for our health but too much sodium can lead it high blood pressure and heart problems
What are the benefits of hard water
Good for bones and teeth
reduces risk of Heart problems
increases overall lifespan
reduces risk of intestinal cancers
Tastes better
brewers prefer it for making beer
Author
Anonymous
ID
212128
Card Set
GCSE CHemistry 3
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Updated
2013-04-08T13:44:30Z
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