Using Resources Flashcards
What is corrosion?
Destruction of materials by chemical reactions with substances in the environment
An example of corrosion
Rusting
What must be present for iron to rust?
Air and water
Ways to add barrier to prevent corrosion
Greasing
Painting
Electroplating
How can corrosion be prevented?
Applying a coating that acts as a barrier
what happens to aluminium to prevent further corrosion
A layer of aluminium oxide is formed on the surface which protects the metal
What is sacrificial protection?
When a coating contains a more reactive metal (e.g. zinc used to galvanised iron)
What form are most metals found in for everyday use?
Alloys
What is bronze an alloy for?
Copper and tin
What is brass an alloy for?
Copper and zinc
What is gold usually alloyed with in jewelry?
Silver, copper and zinc
Why is gold alloys in jewelry?
It is too soft when pure and expensive
What proportion is the gold in the alloy measured in?
Carats,
24 carat is 100% gold
18 carat is 75% gold
What is used to make the alloy steel?
Iron with specific amounts of carbon an other metals
What is a property of high carbon steel?
Brittle
What is a property of low carbon steel?
Softer than high carbon and more easily shaped
what type of steel is resistant to corrosion?
Stainless steel
What is added to steal to turn it into stainless steel?
Chromium and nickel
What is the most common type of glass used?
Soda lime glass
How is soda lime glass made?
By heating a mixture of sand, sodium carbonate and limestone
What is borosilicate glass made from?
Sand and boron trioxide
How does the melting point compare between soda lime glass and borosilicate glass?
Borosiliate glass melts at a higher melting point
How are clay ceramics, including pottery on bricks made?
By sharing wet clay
Then heating in a furnace
What are the properties of polymers depend on?
Depends upon what monomers they are made from and the conditions used to make them
Two types of polyethylenes?
Low density (ld)
High density (hd)
How can you make two types of polyethylene?
By changing conditions
Eg use a catalyst
What do you thermosoftening polymers do when they are heated
Melt
What do you thermosetting polymers do when they are heated
They do not melt
What is the structure of a thermosoftening polymer?
Have weak intermolecular forces between polymer chains, so easily broken (hence melt when they are heated)
What is the structure of a thermosetting polymer?
Have strong covalent bonds between polymer chains, so require lots of heat to overcome
What is a composite?
A substance made of two materials
How are the two types of material combined in a composite?
- A matrix or bind
- Reinforcement
(The matrix binds together fibres/fragments of the reinforcement material)
Eg reinforced concrete
Matrix =concrete
Reinforcment/fibre = steel
Eg surfboard containing glass fibre surrounded by a polyester
Matrix =polyester
Reinforcement/fibre = glass fibre
What is the haber process?
A way to manufacture ammonia
What can ammonia be used to make?
Nitrogen based fertilisers
What are the raw materials for the Haber process?
Nitrogen and hydrogen