C10 - Using Resources Flashcards
Define a natural resource
Natural resources form without any human input
Define finite resources
Finite resources can’t form quickly enough to be considered replaceable.
Define sustainable development
An approach to development that takes into account the needs of people today without damaging the lives of future generations
What is a life cycle assessment?
A life cycle assessment is carried out to assess the environmental impact of a product in each stage of its life from start to end.
What are the 5 stages of life cycle assessments?
1) extracting
2) manufacturing
3) transportation / distribution
4) use of product
5) disposal of product
Define potable water
water that is safe to drink (not pure)
What are pros and cons of desalination?
+ good for countries with a lack of water supply
- requires lots of energy
Describe the process of desalination
- salt water is heated
- water evaporates at 100 ℃
- water vapour rises and travels to condenser
- water vapour cools and condenses
- forms pure potable water
Describe the 3 main steps in the ground water method for getting potable water
- sedimentation of small particles (settle at the bottom of the water)
- filter out the sand and gravel
- sterilisation to kill harmful bacteria/microbes
What can you use to sterilise?
- chlorine
- ultraviolet light
- ozone
What are pros and cons of the ground water method?
+ not many steps
+ doesn’t require lots of energy
- requires a suitable water source
Describe the main steps of the waste treatment method of obtaining potable water
- screened - large objects and grit are filtered out
- sedimentation - heavy solids move to the bottom, forming a sludge and lighter effluent floats on top
- aerobic digestion of effluent - effluent is broken down by bacteria
- anaerobic digestion of sludge - sludge is broken down by bacteria
What are some pros and cons of waste treatment?
+ reuses waste water
+ uses less energy than desalination
- requires several steps
- may require additional treatment (which involves harmful chemicals)
What 2 things influence a property of a polymer?
- which monomers they’re made from
- the conditions used to make them
Describe low density polyethene
- made from ethene
- at a moderate temperature under high pressure
- flexible - good for bags and bottles
Describe high density polyethene
- made from ethene
- at lower temperature and pressure
- rigid - used for drainpipes
Describe thermosoftening polymers
- contain individual polymer chains intertwined together (weak forces)
- can melt
- can be recycled
Describe thermosetting polymers
- contains monomers that can form cross links between the polymer chains - hold the chains together in a solid structure
- can’t melt - just burns
- can’t be recycled
What are ceramics?
non-metal solids with high melting points that aren’t made from carbon-based compounds
Name the 2 types of glass
- soda lime
- borosilicate
Describe soda lime glass
- made from sand, sodium carbonate and calcium carbonate
- used for windows, containers etc.
- most common type of glass
Describe borosilicate glass
- made from sand and boron trioxide
- used for ovenware
- has a higher melting point than soda-lime glass
Describe clay ceramics
- made by shaping wet clay and heating in a furnace
- hard, unreactive and resistant to heat
Define a composite
a material made up of 2 or more different materials
Describe fibreglass
- consists of fibres of glass embedded in a matrix made of polymer
- low density but very strong
- used for building materials
Describe concrete
- made from sand and gravel embedded in cement
- very strong
- used for building materials
Describe wood
- natural composite of cellulose fibres held together by an organic polymer matrix
Describe carbon fibre
- consists of either long chains of carbon atoms bonded together or carbon nanotubes embedded in a polymer matrix
- very strong and light - good for sports equipment
Describe the general properties of ceramics
- insulators of heat and electricity
- brittle and stiff
Describe the general properties of polymers
- insulators of heat and electricity
- can be flexible and easily moulded
Describe the general properties of metals
- malleable
- good conductors of heat and electricity
- shiny
- stiff
Describe bioleaching
- uses bacteria to convert metal compounds into soluble metal compounds
- this can then undergo reduction/electrolysis
Describe phytomining
- plants are grown in soil that contains the metal
- the metal builds up in their leaves
- leaves are harvested and burned
- ash is collected and can undergo reduction/electrolysis
What are the 2 ways to extract a metal from low-grade ores?
- bioleaching
- phytomining
Define corrosion
the destruction of materials by chemical reactions with substances in the environment
What is the word equation for rust?
iron + oxygen + water –> hydrated iron (III) oxide
Why isn’t aluminium completely destroyed by corrosion?
- it forms an aluminium oxide layer, when reacting with the oxygen in the air
- this acts as a barrier and prevents contact with air
Rust requires both …
water and oxygen
What are the 2 main ways to prevent rusting?
- coat the iron with a barrier (e.g painting, electroplating, oiling)
- sacrificial method - placing a more reactive metal with the iron so water and oxygen react with the sacrificial metal instead of the iron
What is the equation for the haber process?
N₂ + 3H₂ <–> 2NH₃
What are the conditions required for the haber process?
- 450℃
- 200 atm
- iron catalyst
Which reaction is exo and endothermic in the haber process?
- the forward reaction is exothermic
- the reverse reaction is endothermic
Why is the temperature in the haber process compromised?
- high temp means an increased rate of reaction
- high temp means a smaller yield
Why is the pressure in the haber process compromised?
- high pressure means a faster rate of reaction
- high pressure means a bigger yield
- any higher than 200atm would be dangerous and expensive (to build and maintain)
Why is an iron catalyst used in the haber process?
- it increases the rate of reaction
- and has no effect on yield
Describe how the haber process works
- gases pass over the iron catalyst
- ammonia is cooled, liquefied and removed
- hydrogen and nitrogen gases are recycled so nothing is wasted
Where do they get the hydrogen and nitrogen from for the haber process?
- air
- natural gas (methane)
Describe NPK fertilisers
- they contain nitrogen, phosphate and potassium
- they are widely available, easy to use, no smell and contain the correct nutrients
Describe producing ammonium nitrate in industry
reaction is carried out in giant vats
+ can produce higher concentrations
- very exothermic (dangerous)
Describe producing ammonium nitrate in the lab
smaller scale - through titration or crystallisation
+ less heat is released (safer)
- get low concentrations
Why is ammonium nitrate a good compound to use in a fertiliser?
it has nitrogen from two sources
Phosphate rock + nitric acid –>
phosphoric acid + calcium nitrate
Phosphate rock + sulfuric acid –>
calcium sulphate + calcium phosphate
Phosphate rock + phosphoric acid –>
calcium phosphate
