Water Flashcards
(17 cards)
What are the three stages to water treatment?
Sedimentation
Filtration
Chlorination
What happens during the sedimentation stage?
Water is stored in the settling tanks, larger particles sink to the bottom. Water is drawn off and sediment is left behind
What happens during the stage of filtration?
Water is passed through a system of filters which remove small particles. Bacteria can still pass through the filters
What happens during the stage of chlorination?
Chlorine is added to the water, kills the bacteria. The water is fit for drinking
Why is conserving water important?
Humans need it to drink
Needed for farms to grow food
Water is important in any habitat. If changed some species may not survive.
Washing things needs water
What are some ways of conserving water?
Having shower instead of bath
Repairing dripping taps
Only use washing machine when full
Don’t use too much water to flush toilet
What is the desalination of water?
Removing the salt from sea water
What are the problems associated with the desalination of water?
The process used more energy than processes used to produce drinking water, it is more expensive
Produces greenhouse gases
The salty water left behind is a pollutant
Difference between temporary hard water and permanent hard water?
Temporary hard waters hardness can be removed by boiling, permanents can’t.
How can you tell the difference between hard and soft water..
By seeing how well the water lathers when soap is added and shaken, soft water lathers easily
How can you tell if the water is temporary hard water?
The water sample with produce more lather only after it has been boiled
Is it possible for a water sample to have a mixture of permanent and temporary hard water?
Yes
How does boiling remove temporary hardness?
It converts the hydrogencarbonates of calcium and magnesium into carbonates p, which are insoluble and from a precipitate.
How can permanent hardness of water be removed?
Adding sodium carbonate. The cl and mg ions bond with the carbonate ions, meaning that less detergent has to be used. This is cheap
Passing the water through and ion exchange column. This removes the cl and mg ions and replaces them with sodium ions, which do not cause hardness. This is expensive
Advantages of hard water?
Many people think it tastes nicer than soft
Calcium and magnesium are essential minerals in the diet
Magnesium in hard water may give some protection against heart disease
Disadvantages of hard water
Temporary hard water can produce deposits which clog and damage hot water pipes and kettles
Hard water requires more soap to clean effectively
Treating permanent hard water in order to save on detergent can produce deposits on washed clothes
Where does our drinking water come from?
Rivers, lakes or underground sources and stored in reservoirs before being treated
