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C10: Quiz 4 – Answers
C10: Quiz 4 – Answers
1)
a) Potable water is water that is safe for humans to drink
b) Potable water is not pure water as it contains dissolved substances
c) 6.5 to 8.5
2)
a) River, lakes and revivors
b) Ground water
c) Surface water
3)
a)
i) The wire mesh removes large pieces of debris like twigs and weeds
ii) The filter bed removes very small particles and breaks down organic matter
b)
i) To kill harmful microorganism like pathogens, bacteria or microbes
ii) Bubble chlorine gas through the water, shine ultraviolet light at the water or use ozone
c) Relatively cheap
4)
a) Desalination and reverse osmosis
b) Expensive
c) Countries would only use these methods if there was very little or no fresh water available (such as the United Arab Emirates)
5)
a)
a) Potable water is water that is safe for humans to drink
b) Potable water is not pure water as it contains dissolved substances
c) 6.5 to 8.5
2)
a) River, lakes and revivors
b) Ground water
c) Surface water
3)
a)
i) The wire mesh removes large pieces of debris like twigs and weeds
ii) The filter bed removes very small particles and breaks down organic matter
b)
i) To kill harmful microorganism like pathogens, bacteria or microbes
ii) Bubble chlorine gas through the water, shine ultraviolet light at the water or use ozone
c) Relatively cheap
4)
a) Desalination and reverse osmosis
b) Expensive
c) Countries would only use these methods if there was very little or no fresh water available (such as the United Arab Emirates)
5)
a)
b) We should check the pH of the water; it should be between 6.5 and 8.5
c) We place the sea water in a distillation flask and place the flask on top of a tripod with a Bunsen burner underneath. We also attach a rubber pipe from a cold tap to the condenser; water from the cold tap goes into the condenser at the bottom and out of the condenser at the top. The next step is to turn the Bunsen burner on, which will heat the distillation flask. As the distillation flask is heated up, the water in the sea water evaporate and turns into a gas (water vapour). The water vapour then rises up the distillation flask and move down the condenser. The condenser causes the water vapour to condense and turn into a liquid. The water then travels down the condenser and into a beaker
d) Left in the distillation flask
6)
a) It allows us to obtain potable water when there is no fresh water available
b) The two negatives are:
7)
a) Reverse osmosis works by firing water at a very high pressure at a membrane. The membrane is partially permeable, which means that the membrane will allow the small water molecules through but will not allow the much larger ions and other molecules to pass through the membrane (the salt cannot pass through). The water that passes through the membrane will be potable water
b) The two negatives are:
c) We place the sea water in a distillation flask and place the flask on top of a tripod with a Bunsen burner underneath. We also attach a rubber pipe from a cold tap to the condenser; water from the cold tap goes into the condenser at the bottom and out of the condenser at the top. The next step is to turn the Bunsen burner on, which will heat the distillation flask. As the distillation flask is heated up, the water in the sea water evaporate and turns into a gas (water vapour). The water vapour then rises up the distillation flask and move down the condenser. The condenser causes the water vapour to condense and turn into a liquid. The water then travels down the condenser and into a beaker
d) Left in the distillation flask
6)
a) It allows us to obtain potable water when there is no fresh water available
b) The two negatives are:
- it is an extremely expensive process
- the waste water is extremely salty, which is quite hard to dispose of
7)
a) Reverse osmosis works by firing water at a very high pressure at a membrane. The membrane is partially permeable, which means that the membrane will allow the small water molecules through but will not allow the much larger ions and other molecules to pass through the membrane (the salt cannot pass through). The water that passes through the membrane will be potable water
b) The two negatives are:
- it is an extremely expensive process
- the waste water is extremely salty, which is quite hard to dispose of
Questions
1)
a) What is potable water?
b) Is potable water pure water? Explain your answer.
c) What is the pH range for potable water?
2)
a) Fresh water can be found as surface water or ground water. What are the three different places where surface water can be found?
b) Out of surface water and ground water, where is the majority of potable water obtained from in the south of England?
c) Out of surface water and ground water, where is the majority of potable water obtained from in the North of England and Scotland?
3) This question is all about treating fresh water (surface water or ground water).
a) The first step in treating fresh water is to filter it.
i) The first part of the filtration process involves letting the water pass through a wire mesh, which is known as a screen. Why do we do this?
ii) After the water has passed through the screen, it passes through a filter bed. Why does this happen?
b) After the water has gone through both of the filtration stages, it is sterilised.
i) Why do we sterilise the water?
ii) Give the three ways that we can sterilise the water.
c) Is the process of obtaining potable water from fresh water relatively cheap or relatively expensive?
4) We can obtain potable water from sea water in two different ways.
a) Give the names of these 2 different ways to obtain potable water from sea water.
b) Are these 2 methods of obtaining potable water from sea water relatively cheap or relatively expensive?
c) Why would a country choose to obtain potable water from sea water rather than from fresh water?
5) We can undertake a distillation experiment in a lab to obtain potable water from sea water.
a) Draw a sketch for the setup of this experiment and label all of the different pieces of apparatus.
b) Before we use the apparatus to obtain potable water, what must we check regarding the water?
c) Describe how the apparatus that you have drawn in part a can be used to obtain potable water.
d) Where will the salt and other impurities in the sea water be left?
6)
a) Give one positive of using distillation on an industrial scale to obtain potable water.
b) Give two negatives of using distillation on an industrial scale to obtain potable water.
7) Another way that we can obtain potable water from sea water is to do reverse osmosis.
a) Explain the steps involved in reverse osmosis.
b) Give 2 negatives of reverse osmosis.
1)
a) What is potable water?
b) Is potable water pure water? Explain your answer.
c) What is the pH range for potable water?
2)
a) Fresh water can be found as surface water or ground water. What are the three different places where surface water can be found?
b) Out of surface water and ground water, where is the majority of potable water obtained from in the south of England?
c) Out of surface water and ground water, where is the majority of potable water obtained from in the North of England and Scotland?
3) This question is all about treating fresh water (surface water or ground water).
a) The first step in treating fresh water is to filter it.
i) The first part of the filtration process involves letting the water pass through a wire mesh, which is known as a screen. Why do we do this?
ii) After the water has passed through the screen, it passes through a filter bed. Why does this happen?
b) After the water has gone through both of the filtration stages, it is sterilised.
i) Why do we sterilise the water?
ii) Give the three ways that we can sterilise the water.
c) Is the process of obtaining potable water from fresh water relatively cheap or relatively expensive?
4) We can obtain potable water from sea water in two different ways.
a) Give the names of these 2 different ways to obtain potable water from sea water.
b) Are these 2 methods of obtaining potable water from sea water relatively cheap or relatively expensive?
c) Why would a country choose to obtain potable water from sea water rather than from fresh water?
5) We can undertake a distillation experiment in a lab to obtain potable water from sea water.
a) Draw a sketch for the setup of this experiment and label all of the different pieces of apparatus.
b) Before we use the apparatus to obtain potable water, what must we check regarding the water?
c) Describe how the apparatus that you have drawn in part a can be used to obtain potable water.
d) Where will the salt and other impurities in the sea water be left?
6)
a) Give one positive of using distillation on an industrial scale to obtain potable water.
b) Give two negatives of using distillation on an industrial scale to obtain potable water.
7) Another way that we can obtain potable water from sea water is to do reverse osmosis.
a) Explain the steps involved in reverse osmosis.
b) Give 2 negatives of reverse osmosis.