USING RESOURCES Flashcards
What are ceramics?
Non-metal solids with high boiling/melting points
Not made from carbon-based compounds
(Can be made from clay)
How can clay be made as a ceramic?
When dug up it is soft so can be moulded
Fired at high temps to harden to form a clay ceramic
(Pottery and bricks)
How can glass be made as a ceramic?
Can be moulded when hot
Brittle when thin
How is soda lime glass made?
Made from heating limestone, sand and sodium carbonate until it melts then cools
What is borosilicate glass?
Has higher melting point than soda-lime glass
Made by mixing sand and boron trioxide
What are composites?
Made of one material embedded in another
What is an example of a composite?
Fibres or fragments (reinforcement) of material surrounded by a matrix (acts as a binder)
What is fibreglass?
Fibres of glass embedded in a matrix made of polymer (plastic)
What can fibreglass be used for?
Skis
Boats
Surfboards
What is carbon fibre?
Polymer matrix
Reinforcement of either chains of carbon atoms bonded together or carbon nanotubes
What does a composite contain?
Reinforcement (fibre/fragment of material)
Matrix (surrounds the reinforcement)
What affect the properties of a polymer?
How it’s made and what it’s made from
How is low density poly(ethene) made?
Moderate temp and high pressure with a catalyst
(Flexible for bags and bottles)
How is high density poly(ethene) made?
Lower temperature and pressure with a different catalyst
(More rigid so for water tanks etc)
What influences the properties of poly(ethene)?
The catalyst
Reaction conditions (temp and pressure)
What is poly(ethene) made from?
Ethene
What determine the type of bonds that form between polymer chains?
The monomers that a polymer is made from
What determines the properties of a polymer (bonds)?
The monomers which create different weak bonds
What do thermosoftening polymers contain?
Individual polymer chains entwined together with weak forces (melt and remould)
What do thermosetting polymers contain?
Monomers that form cross links between polymer chains so solid structure (strong, hard, rigid)
What are the properties of ceramics?
Insulators of heat and electricity
Brittle
Stiff
What are the properties of composites?
Depend on the matrix/binder and reinforcement
What are the properties of metals?
Good conductors of heat and electricity
Ductile (drawn into wires)
Shiny
Stiff
What are the properties of polymers?
Insulators of heat and electricity
Flexible
Can be moulded easily
What is bronze made out of?
Tin and copper
What is brass made out of?
Copper and zinc
What metals can be used to harden gold (alloy)?
Zinc
Copper
Silver
How is aluminium made stronger?
Alloyed with small amounts of other metals to make it stronger
What is corrosion?
Where metals react with substances in their environment and are gradually destroyed
What is the word equation for when iron rusts?
Iron + oxygen + water -> hydrated iron (III) oxide
What is needed for iron to rust?
Oxygen and water
Where does corrosion occur?
On the surface of a material where it is exposed to air