Using Resources Flashcards
What is a ceramic?
- non metal solid
- have high melting point that aren’t carbon based compounds
What are some examples of ceramics?
- clay ceramic
- glass
How is glass created?
Heat a mixture of limestone, sand and sodium carbonate until it melts
When mixture cools it comes out as glass
How is clay ceramic formed?
When clay is fired at high temperatures, it hardens to form a clay ceramic
What is a composite?
- made of one material embedded in another
- fibres or fragments of a material are surrounded by a matrix acting as a binder
What are some examples of composites?
- fibreglass
- carbon fibre
- concrete
- wood
How is low density (LD) poly(ethane) made?
- made from ethene at a moderate temperature under a high pressure and with a catalyst
- used for bags and bottles as it is flexible
How is high density (HD) poly(ethene) made?
- made from ethene at a lower temp and pressure with a different catalyst
- more rigid and is used for water tanks and drainpipes
What is a thermosetting polymer?
Contains monomers that can form cross links between the polymer chains which holds chains together in a solid structure
- don’t soften when they’re heated
- strong, hard and rigid
What is a thermosoftening polymer?
Contain individual polymer gains entwined together with weak forces between chains
-can be melted and remoulded
What properties do ceramics have?
-good insulators of heat and electricity
-brittle and stiff
Eg porcelain and bricks
What properties do polymers have?
- good insulators of heat and electricity
- can be flexible and easily moulder
- used in clothing and insulators in electrical items
What properties do composites have?
Their properties depend on the matrix/binder and the reinforcement used to make them
-have many uses
What properties do metals have?
-generally malleable
-good conductors of heat and electricity
-ductile (drawn into wires)
-shiny and stiff
Eg used in electrical wires, cutlery etc
How is an alloy created?
Made by adding another element to metal
This disrupts the structure of the metal, making alloys harder than pure metals
How are steels created?
Adding a small amount of carbon and sometimes other metals to pure carbon
What is corrosion?
Where metals react with substances in their environment and are gradually destroyed
-happens on the surface of a material where it’s exposed to air
How does iron “rust” ?
Needs to be in contact with both oxygen and water which are present in the air
-destroys the object as the rust flakes off leaving more iron to rust again
What is the formula for hydrated iron (lll) oxide? (Rusting of iron)
iron + oxygen + water —-> hydrated iron (lll) oxide (iron is oxidised)
What happens when aluminium corrodes?
- things made from Al are not destroyed by corrosion
- because the aluminium oxide formed doesn’t flake away
- it forms a nice protective layer that sticks firmly to aluminium to stop any further reaction taking place unlike iron
Why will the mass of a rusty nail increase?
Because iron atoms in nail have bonded to oxygen and water molecules
-results in a compound that is heavier than iron alone
How can rusting be prevented?
- painting/coating with plastic (barrier from oxygen and water)
- electroplating (coat iron with layer of different material)
- oiling/greasing
What is a finite resource?
- non-renewable
- aren’t formed quickly enough to be considered replaceable
Examples of finite resources?
- fossil fuels
- nuclear fuels-uranium & plutonium
- minerals and metals in ores in earth
