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