C10 Natural resources Flashcards
What do we use the Earth’s resources for?
Warmth, shelter, food and transport
How do we use agriculture to maximise these resources?
To provide food, timber, clothing and fuel
What does the term finite mean?
There is a limited amount so we will run out of it eventually
What is potable water?
Water that is safe to drink
What does water need to have to be classed as potable?
Low enough levels of dissolved salts and microbes
How can fresh water be made potable?
Filtering the water through filter beds and then sterilising it
How can water be sterilised?
Using chlorine, ozone of UV light
How can salt water be made potable?
Remove the salt by distillation or reverse osmosis
Why fresh water a better source of potable water than salt water?
It requires less energy to make potable
How are potable and pure water different?
Pure water has no other chemicals in it, potable has other chemicals in it but at low enough levels so it is safe to drink
How is sewage treated before being released into the environment?
Screening and grit removal, sedimentation, anaerobic digestion of sewage sludge, aerobic treatment of effluent
Why is fresh water a better source of potable water than waste water?
There are a lot more stages in making waste water potable
What are low grade copper ores?
Rocks that have a small percentage of copper in them
Why are new methods of extraction needed?
“Traditional methods of digging, moving and disposing of large amounts of rock are more expensive, use lots of fuel and produce lots of waste.
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What is phytomining?
Using plants to absorb metal compounds from the ground. The 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
What are the 4 stages of a life cycle assessment?
Extracting and processing the raw materials, making and packaging the product, using the product, disposing of the product
What is looked at at each stage in a LCA (life cycle assessment)?
The water, resources and energy used, the pollution and waste produced, including affects of transport.
Why is it hard to quantify pollution effect?
It is subjective, people may disagree about which pollutant is worse.
Why are partial LCA a problem?
They can be misused to support a claim for advertising that might not be true. They can be biased.
What are the advantages of reducing use of or reusing and recycling materials?
It saves limited resources, saves on energy sources, reduces waste products and environmental impact
Give some examples of materials that come from finite resources
Metals, glass, building materials, clay ceramics and plastics
What is a problem with quarrying and mining the earth?
Lots of waste produced, environmental impacts
How can we reduce the use of resources?
Reuse glass bottles, recycle materials for different uses.
What is corrosion?
Corrosion is when a material reacts with substances in the environment, usually water and/or air
What is rusting?
Rusting is an example of corrosion. It is when iron reacts with water and air.
How can corrosion be prevented?
Painting, greasing or plating a metal to form a barrier so water and air can’t react with it
What is galvanising?
This is when zinc (which is more reactive than iron) is coated on iron so that it reacts instead of the iron.
Why does aluminium not corrode much?
A layer of aluminium oxide forms and prevents further corrosion
What is bronze?
An alloy of copper and tin
What is brass?
An alloy of copper and zinc
Give an example of a use of bronze and brass
Bronze is used in coins, brass is used in electrical fittings.
Give an example of a use of gold alloys
Alloys of gold are used in jewellery as it is cheaper but harder
Give an example of a use of aluminium alloys
Aluminium alloys are light so used in aircraft
Give examples of uses of steel alloys
High carbon steel is used in cutting tools as it is strong, low carbon steel is used to make screws as it is soft and easy to shape, stainless steel is used in construction as it is hard and resists corrosion
How is soda-lime glass made?
By heating sand, sodium carbonate and limestone
How is borosilicate glass made and why is it needed?
It is made from sand and boron trioxide, it has a higher melting point so is used in lab equipment and cooking
How are clay bricks and pottery made?
Wet clay is shaped and then heated in a furnace
What are thermosoftening and thermosetting polymers?
Thermosoftening polymers melt when heated as they have weak intermolecular bonds between the polymer chains. Thermosetting polymers have strong cross links between polymer chains so do not melt.
What are HDPE and LDPE and how are they made?
LDPE is low density poly(ethene) and HDPE is high density poly(ethene) they are both made from ethene but LDPE is made under high pressure
What are the difference between HDPE and LDPE?
HDPE has straight polymer chains while LDPE chains are branched. This means HDPE chains can get closer together so the intermolecular bonds are stronger and the material is stronger too.
What are composite?
Composites are a mixture of two materials with the product having a combination of the properties of each material.
What are some example of composites?
Reinforced concrete is concrete poured around steel rods, this is less susceptible to bending due to the steel and still difficult to compress due to the concrete
What is the purpose of the Haber process?
To make ammonia which is used in fertiliser
What are the raw materials for the Haber process
Nitrogen and hydrogen
Where do the raw materials for the Haber process come from?
Nitrogen comes from the air and hydrogen comes from natural gas
Why is a temperature of 450oC used in the Haber process?
A higher temperature gives a high rate of reaction but lowers the yield as the equilibrium shifts to the left. This temperature is a compromise between rate and yield
Why is a pressure of 200 atm used in the Haber process?
A high pressure gives a high rate of reaction and a high yield but high pressures are dangerous and require more expensive equipment. The pressure is a compromise between rate and yield and cost and safety.
Why is an iron catalyst used in the Haber process?
It speeds up the rate of reaction without affecting the yield
How is the ammonia separated from the hydrogen and nitrogen in the Haber process?
The mixture is cooled and as ammonia has the highest boiling point it liquefies first and can be poured off, the hydrogen and nitrogen stay as gasses and get recycled
What do fertilisers contain?
Compounds of nitrogen, potassium and phosphorous
Why are fertilisers an example of a formulation?
They are a designed mixture with appropriate amounts of N, P and K for their use.
How is ammonia used to make fertiliser?
It is reacted with acids to make ammonium salts
How are potassium chloride, potassium sulphate and phosphate rock obtained?
Through mining but the phosphate rock needs to be treated with acid before it can be used as a fertiliser
What is formed when phosphate rock reacts with nitric, sulphuric or phosphoric acid?
Phosphate rock and nitric acid makes calcium nitrate, phosphate rock and sulphuric or phosphoric acid makes calcium phosphate
How does large scale production of fertilisers differ to lab reactions to make the same chemicals?
In industry the process is carried out on a large scale in a continuous process, in a lab the process is much smaller in scale and makes batches of the chemicals. The purity is easier to control in a lab,
