Using Materials

Question 1

What is corrosion

Answer 1

Gradual destruction of metals because of chemical reactions between metals and the oxgmygen and water around them

Eg rusting of iron

Question 2

Rusting experiment

Answer 2

Take 3boiling tube and put iron nail inside of each under 3 different sets of conditions to see how it rusts

Nail completely under water = only water = no rust

Nail not covered in any water = only air = no rust

Nail half half in water and air = water and air = rust

Question 3

Preventing corrosion

Answer 3

Coatings - act like a barrier eg painting and greasing
A disadvantage is that any damage to the coating leads to the metal becoming exposed

Sacrificial method - metal that requires protection has a more reactive metal attached to it. Means the water and air will go for the more reactive sacrifice metal

Galvanising - hybrid of coatings and sacrificial methods. Metal that needs protecting is sprayed with a more reactive metal which initially acts as a coating. If the coating is damaged it will continue to protect as the sacrificial method

Question 4

alloys

Answer 4

Metal that is mixed with other elements

By adding these to ther elements we can change a metals properties

Examples of alloys :
Bronze
Brass
Gold
steel
aluminium

Question 5

Ceramics

Answer 5

Inorganic non metallic solids

Eg pottery and bricks
Glass

Question 6

Polymers

Answer 6

Properties are determined by conditions it’s made in and monomers its made from

Depending on the monomer a polymer can be thermosoftening or thermosetting

Poly ethene come in two different forms depending on conditions it’s made in , lowdensity polythene or high density polythene

Question 7

Thermosoftening vs thermosetting

Answer 7

Depends on monomers

Thermosoftening polymers: have individual chains that are held together by weak Intermolecular forces.
When heated they soften and can be remoulded

Thermosetting polymers: have chains in a solid structure as they t have cross links.
High strength, hardness, not softened when heated, rigid

Question 8

Low density poly ethene vs high density poly ethene

Answer 8

Low density : flexible polymer produced using moderate temp high pressure and a catalyst

High density : rigid polymer produced using a lower temperature, lower pressure and different catalyst

Question 9

Composites

Answer 9

Made by embedding a material known as the reinforcement into the matrix.

Eg

Fibre glass- reinforcement = glass fibres, matrix = polymer

Concrete - reinforcement = sand and gravel, matrix = cement

Carbon fibre - reinforcement = carbon fibres, matrix = polymer