C10- Using Resources Flashcards
What type of glass do we use the most?
Soda Lime Glass
What are the two types of glass?
Soda-lime glass
Borosilicate glass
How is soda lime glass made?
It is made by heating a mixture of sand, sodium carbonate and limestone
How is borosilicate glass made?
It is made by heating sand and boron trioxide
Does soda-lime or borosilicate glass melt at a lower temperature?
Soda-lime melts at a lower temperature than borosilicate
Give two examples of clay ceramics?
Pottery
Bricks
How are clay ceramics made?
They are made by shaping wet clay and then heating it in a furnace to harden it
What two things do the properties of polymers depend on?
-What monomers they are
made from
-The conditions under which they are made
How is a polymer formed?
Joining together a large number of monomers
What conditions can affect the properties of a polymer?
Temperature
Pressure
Use of a catalyst
Is low-density or high-density poly(ethene) harder?
High-density poly(ethene) is harder than low-density poly(ethene)
What are both low density and high density poly(ethene) are produced from?
Ethene
Why do low density and high density poly(ethene) have different properties?
They are produced under different reaction conditions and with different catalysts
What is the structure of a thermosetting polymer?
Why does this affect its properties?
Polymer chains with many, strong cross links. This means it doesn’t melt when it is heated.
What is the structure of a thermosoftening polymer?
Why does this affect its properties?
Individual, tangled polymer chains which can be easily separated.
This means it can easily melt when it is heated.
How do the structures of high density and low density poly(ethene) differ?
How does this affect their properties?
Low density polyethene has weaker forces of attraction as the chains are further apart. This means it has a low melting point and is soft.
High density polyethene has stronger forces of attraction as the chains are closer together. This means it has a high melting point.
What are composites made of?
A combination of two materials:
-a reinforcement- consists of fibres/fragments of one material
-a matrix/binder material that surrounds the reinforcement
Two examples of composites
-What are they made of?
-What are they used for?
Carbon fibre composite:
-Reinforcement= fibres of carbon
Matrix= plastic resin
-Very strong and light so is used for cars and aircraft parts.
Reinforced concrete
-Reinforcement= steel bars
Matrix= concrete
- Extremely strong so used to make buildings
What is corrosion?
Corrosion is the destruction of materials by chemical reactions with substances in the environment
What is rusting an example of?
Corrosion
What is needed for iron to rust?
Air and water
How can corrosion be prevented?
Give examples
Corrosion can be prevented by applying a coating that acts as a barrier, such as:
-greasing
-painting
-electroplating
-sacrificial protection (e.g. galvanisation)
How is sacrificial protection provided?
Give an example
A more reactive metal is used to coat another less reactive metal in order to prevent corrosion
Example: zinc is used to galvanise iron.
Most metals in everyday use are _____
alloys
What is bronze an alloy of?
Copper and tin.
What is brass an alloy of?
Copper and zinc
What is gold used in?
What is it an alloy of?
Gold used as jewellery
It is usually an alloy with silver, copper and zinc.
What is the proportion of gold in the alloy is measured in?
Carats
What proportion of the alloy is gold in 24 carat gold?
100%
What proportion of the alloy is gold in 18 carat gold?
75%
What are steels?
Steels are alloys of iron that contain specific amounts of carbon and other metals
Properties of high carbon steel
-Hard
-Brittle
Properties of low carbon steel
-Softer
-Easily shaped
What are stainless steels?
Steels containing chromium and nickel
Properties of stainless steels
-Hard
-Resistant to corrosion.
Are aluminium alloys high or low density?
Low
The Earth’s resources of metal ores are _____
Limited
Copper ores are becoming _____
Scarce
Name two new ways of extracting
copper from low-grade ores
-Phytomining
-Bioleaching
What do phytomining, and bioleaching avoid?
They avoid traditional mining methods of digging, moving and disposing of large amounts of rock
Stages of phytomining
-Plants are planted on low-grade ore sites
-As the plants grow, copper compounds are taken up by the roots
-The plants are harvested and burned to ash which contains the copper compounds
-The ash is dissolved in sulphuric acid to form a solution which contains copper compounds
-The solution is displaced by scrap iron and electrolysis is used to obtain pure copper
Stages of bioleaching
-low-grade copper sites are flooded with bacteria
-bacteria absorb copper from the surroundings
-liquid is passed through a large colony of bacteria to produce a leachate solution, which contains copper compounds
-copper is extracted from the solution by displacement using scrap iron and then electrolysis
What do humans use the Earth’s resources for?
To provide warmth, shelter, food and transport
Natural resources, supplemented by agriculture, provide _______
Food, timber, clothing and fuels
What are finite resources from the Earth, the oceans and the atmosphere processed for?
To provide energy and materials
What are finite resources?
Resources that cannot be replenished at the rate they are being used up, so they will run out
What are renewable resources?
Resources that can be replenished at the rate they are being used up, so they won’t run out
Examples of natural products that are supplemented or replaced by agricultural and synthetic products
Fertiliser- used to use manure but now use ammonia produced by the Haber process
Cotton- used to be natural but now most is synthetic
What is potable water?
Water that is safe to drink
What should potable water always have?
Sufficiently low levels of dissolved salts and microbes
How is potable water produced from rain water (fresh water)?
1) choosing an appropriate source of fresh water
2) passing the water through filter beds to remove any large pieces of rock, twigs etc
3) sterilisation, with sterilising agents such as chlorine, ozone or ultraviolet light, to remove any bacteria and microbes
What must be done to sea water before it is able to be used as drinking water?
Desalination
Two methods of desalination
-distillation
-processes that use membranes such as reverse osmosis
What is the problem with desalination?
The process requires a lot of energy, making it very expensive
Why are life cycle assessments carried out?
To assess the environmental impact of products at each stage of their production, usage and disposal
Stages of an LCA
-extracting and processing raw materials
-manufacturing and packaging
-use and operation during its lifetime
-disposal at the end of its useful life,
(including transport and distribution at each stage)
Problems with LCAs
-Allocating numerical values to
pollutant effects requires value
judgements, so LCA is not a purely objective process.
-Selective or abbreviated LCAs can be devised to evaluate a product but these can be misused to reach pre-determined conclusions, e.g. in support of claims for advertising purposes
What do humans use the Earth’s resources for?
To provide warmth, shelter, food
and transport
What do natural resources, supplemented by agriculture provide?
They provide food, timber, clothing and fuels
Where do we find finite resources?
The Earth, oceans and atmosphere
Finite resources from the Earth, oceans and atmosphere are processed to provide _______
Energy and materials
What is sustainable development?
Development that meets the needs of current generations without compromising the ability of future generations to meet their own needs
What does chemistry play an important role in?
Improving agricultural and industrial processes to provide new products and in sustainable development
What needs to be removed from sewage and agricultural waste water?
Organic matter and harmful microbes
What needs to be removed from industrial waste water?
Organic matter and harmful chemicals
Stages of sewage treatment
-screening and grit removal
-sedimentation to produce sewage
sludge and effluent
-anaerobic digestion of sewage sludge
-aerobic biological treatment of effluent.
What does the reduction in use, reuse and recycling of materials lead to?
A reduction in the use of limited resources, use of energy sources, waste
and environmental impacts.
What materials are produced from limited raw materials?
Metals, glass, building materials, clay ceramics and most plastics
What are metals, glass, building materials, clay ceramics and most plastics produced from?
Limited raw materials
What does obtaining raw materials from the Earth by quarrying and mining cause?
Environmental impacts
How can glass bottles be reused?
Glass bottles can be crushed and melted to make different glass products
What is done if a product can’t be reused?
It is recycled for a different use
How can metals be reused?
Metals can be recycled by melting and recasting or reforming into different products
What does the amount of separation required for recycling depend on?
The material and the properties required of the final product
How can the amount of iron that needs to be extracted from iron ore be reduced?
When recycling the iron, some scrap steel can be added to iron from a blast furnace
What is the Haber process used for?
To produce ammonia
What can ammonia be used for?
-to produce nitrogen-based fertilisers
-in cleaning products
What are the raw materials for the Haber process?
Nitrogen and hydrogen
Where does the nitrogen used in the Haber process come from?
The air
Where does the hydrogen used in the Haber process come from?
-crude oil
-methane from biogas generators
What conditions are used for the Haber process?
-High temperature (about 450°C)
-High pressure (about 200 atmospheres)
What type of reaction is the Haber process? What does this mean in the context of the process?
Reversible, meaning some of the ammonia produced breaks down into nitrogen and hydrogen
How is the ammonia removed? What happens to the remaining hydrogen and nitrogen?
The ammonia is cooled and liquefied. The remaining hydrogen and nitrogen are recycled back into the system so it can react to produce more ammonia.
Why can’t a very high pressure be used for the Haber process?
It can cause the equipment to explode, so reinforced equipment would have to be used, which is very expensive. Also, the large amount of energy needed to provide the conditions would make it very expensive.
What elements do NPK fertilisers contain?
Nitrogen, phosphorus and potassium
What are NPK fertilisers used for?
To improve agricultural productivity
Advantages of phytomining
-reduces the need to extract new ore by mining
-conserves the limited supply of high-grade copper ores
Disadvantages of phytomining
-slow process
Advantages of bioleaching
-reduces the need to extract new ore by mining
-conserves the limited supply of high-grade copper ores
Disadvantages of bioleaching
-very slow process (can take years)
-some toxic chemicals may be produced which could harm wildlife
What are NPK fertilisers formulations of?
NPK fertilisers are formulations of various salts containing appropriate percentages of the elements
What can ammonia be used to manufacture?
Ammonium salts and nitrates
What compounds that are needed to produce NPK fertilisers are obtained by mining?
-Potassium chloride
-Potassium sulfate
-Phosphate rock
Can phosphate rock be used directly as a fertiliser?
No
How does phosphate rock produce soluble salts that can be used as fertilisers?
Phosphate rock is treated with nitric acid or sulfuric acid to produce soluble salts that can be used as fertilisers
Why does the Haber process use a high temperature instead of a low temperature which moves equilibrium to the right, producing ammonia?
Relying on a low temperature would mean the rate of ammonia production is very slow, so instead yield is compromised for the rate of production
What catalyst is used in the Haber process?
Iron
Phosphate rock reacts with nitric acid to produce ….
Calcium nitrate and phosphoric acid
Phosphate rock reacts with sulfuric acid to produce ….
Single superphosphate (a mixture of calcium sulfate and calcium phosphate)
What is single superphosphate?
A mixture of calcium sulfate and calcium phosphate
Phosphate rock reacts with phosphoric acid to produce…
Triple superphosphate (calcium phosphate)
What is triple superphosphate?
Calcium phosphate
Compare the production of fertilisers in labs and in industry
Labs:
-batch production
-uses less concentrated solutions so is more safe
Industry:
-continuous production
-very concentrated solutions are used so it is a very exothermic reaction, meaning lots of heat is produced so it can be dangerous
Experiment to show conditions needed for corrosion
1) Place 6 nails into 6 test tubes
2) Keep one test tube empty with no lid as a control to compare the other results to
3) Fill the other five test tubes with different things: salty water, pure water, water with a layer of oil, salt, calcium chloride
4) Leave the test tubes on a rack for a week to see how the conditions affect rusting
Experiment to analyse a sample of water
1) Use universal indicator to test the pH of the water.
2) Measure and record the mass of an empty evaporating basin.
3) Pour 10 cm3
water into the evaporating basin and evaporate the water using a bunsen burner until the most of the water has evaporated.
4) Once the evaporating basin is cool, reweigh and record the change in mass.
5) Calculate the mass of dissolved solids in the water.
Experiment to purify a sample of water by distillation
1) Place the water sample in a conical flask and set up the apparatus for distillation.
2) Heat the water gently using a bunsen burner until it boils. Then reduce the heat so the
water boils gently.
3) Collect around 1 cm depth of water in the cooled test tube, then stop turn the bunsen
burner off.
4) Analyse the water you have distilled with cobalt chloride paper
