P2-Topic 10- Using the Earth's resources and obtaining potable water Flashcards
based on 2022 advanced info
What is sustainable development?
Development that meets the needs of current generations without compromising
the ability of future generations to meet their own needs
In the UK, potable water is produced by…? 3
- choosing an appropriate source of fresh water
- passing the water through filter beds to remove any solids
- sterilising to kill microbe
What are the sterilising agents
for potable water?
4
Sterilising agents used for potable water include chlorine, ozone or ultraviolet light.
• Chlorine is a toxic gas so the amount added to water has to be carefully
monitored.
• Using ultraviolet light to kill microbes avoids adding chemicals to the water but is more expensive
How is desalination carried
out?2
by distillation or by processes that use membranes such
as reverse osmosis.
These processes require large amounts of energy.
what are finite resources
resources that have a limited supply that will eventually run out
an example of a natural product that can be replaced by a synthetic one 3
Rubber which is extracted from the sap of trees (called latex)
The replacement material for rubber are polymers which have been developed to specifically replace the rubber in many products
The use of fertilisers to enhance crop yield is an example of this
What is reverse osmosis?3
Sea water is passed through a membrane that only allows through the water
molecules.
It needs high pressure to push the water through the membrane.
The high pressure requires a lot of energy to produce.
What is potable water
water that is safe to drink
How is wastewater produced and how is it treated? 3
-Urban lifestyles and industrial processes produce large amounts of waste water that require treatment before being released into the environment.
• Sewage and agricultural waste water require removal of organic matter and
harmful microbes.
• Industrial waste water may require removal of organic matter and harmful chemicals.
What are the processes involved in sewage treatment? 4
Sewage treatment includes:
- screening and grit removal
- sedimentation to produce sewage sludge and effluent
- anaerobic digestion of sewage sludge
- aerobic biological treatment of effluent
What do new methods of mining avoid in terms
of disadvantages of traditional mining?
Avoids the disadvantages of traditional mining methods of digging, moving and disposing of large amounts of rock
What is phytomining?
using plants to absorb metal compounds.
plants are harvested and then burned to produce ash that contains metal
compounds.
What is bioleaching?
using bacteria to produce leachate solutions that
contain metal compounds.
how can metal extraction be used to obtain the metal 3
metal compounds can be processed to obtain the metal
copper can be obtained from solutions of copper
compounds by displacement using scrap iron or by electrolysis
What is the main advantage and disadvantage of these methods?
need less energy than traditional methods
can work on low concentration ores but are slow to carry out.
Outline the key points of Haber process. Include the use of the product.6
a)H₂ & N₂ gases are passed over Fe catalyst at a high temperature (about 450 °C)
and a high pressure (about 200 atm) to compress gas
b) Fe speeds up the rate of reaction, so that a lower temperature could be used in the process.
c) Some of the hydrogen and nitrogen reacts to form ammonia
d) The reaction is reversible so ammonia breaks down again into nitrogen and hydrogen.
e) On cooling, the ammonia liquefies and is removed.
The remaining hydrogen and nitrogen are recycled = no waste
f) Ammonia is used for production of nitrogen-containing fertilisers.
The Haber process uses high T and p conditions.
Explain why this is so and why this is a compromise.
2
• The reaction is exothermic. An optimum temperature of 450 °C is used. Using a lower temperature
would give a higher yield, but the rate of NH3
production would be too slow.
• A pressure of 200 atm is used. Using a higher pressure would give a higher yield, but would be too expensive, because of the cost of energy to produce the high pressure.
How are compounds of nitrogen, phosphorus
and potassium used?
Compounds of nitrogen, phosphorus and potassium are used as fertilisers to
improve agricultural productivity. NPK fertilisers contain compounds of all three elements
How is industrial production of
NPK fertilisers achieved?
Ammonia can be used to manufacture ammonium salts.
The ammonium sulfate,
phosphate, and nitrate can be produced by reaction of ammonia with the requisite
acid.
How is the phosphate rock utilised in the production of fertilisers?
• Phosphate rock is reacted with nitric acid to produce phosphoric acid and
calcium nitrate.
• Phosphate rock can be reacted with sulfuric acid to produce a mixture of calcium phosphate and calcium sulfate
• Phosphate rock can be reacted with phosphoric acid to produce calcium
phosphate.
