Using resources-PAPER2 Flashcards
Pure gold is described as how many carats?
24, so 18 would be 75% gold.
What are ceramics?
non metal solids with high melting points that aren’t made from carbon based compounds.
What are composites?
Made of one material embedded in another. Fibres of fragments of a material are surrounded by a matrix acting as a binder. The properties of a composite depend on what it has been made from.
What are two important things that can influence the properties of polymers?
How its made and what its made from.
Give one difference between thermosetting and thermosoftening polymers
You can melt and re mould these plastics- thermosoftening
thermosetting polymers do not soften when heated.
If a metal doesn’t have the properties needed what is used?
An alloy (made by adding another element to the metal) It often makes them harder.
Properties of of a polymer?
Insulators of heat and electricity, can be flexible amd easily moulded.
Properties of ceramics?
Insulators of heat and electricity, they are brittle and stiff.
Properties of composites?
The properties of composites depend on the matrix/binder used to make them.
Properties of metals?
Malleable, good conductors of heat and electricity.
They’re ductile (drawn into wires) shiny and stiff.
What is corrosion?
Where metals react with substances in their environment and are gradually destroyed.
Both……. and ……. corrode much more than ……
Iron and steel corrode much more than alluminium.
Both air and water are needed for….. to rust
Iron
What are the two main ways to prevent rusting?
Sacrificial method, this involves placing a more reactive metal e.g. magnesium with the iron. The water and oxygen then react with the magnesium
Coat it with a barrier to keep out the oxygen and water.
Why will an iron nail that’s been galvanised with zinc rust after just an iron nail?
As the zinc is more reactive but doesn’t rust therefore the water and oxygen react with the zinc instead.
