Topic 10: Using Resources Flashcards
What are the 2 main groups of ceramics?
- Clay ceramics
- Glass
What makes clay ideal for making pottery and bricks?
Its ability to be moulded when wet and then hardened
What is most glass made from?
Soda-lime glass
What is soda-lime glass composed of? [3]
- Limestone
- Sand
- Sodium carbonate (soda)
What is different about borosilicate glass?
Has a higher melting point than soda-lime glass
What is borosilicate glass composed of? [2]
- Sand
- Boron trioxide
What makes glass good for windows? [3]
- Transparent
- Strong
- Good thermal insulator
What is a composite material?
A material consisting of two or more materials with different properties, which have been combined to produce a material with more desirable properties
What are the 2 components of a composite material?
- The reinforcement
- The matrix
What does fibreglass (composite material) consist of? [2]
Fibres of glass [1] embedded in a matrix made of plastic [1]
Why is fibreglass good for things like skis, boats and surfboards?
It has a low density but is very strong
What does carbon fibre (composite material) consist of? [2]
Carbon fibres [1] embedded in a matrix made of plastic [1]
Why is carbon fibre good for things like sports cars?
Light but very strong
What does concrete (composite material) consist of? [2]
Aggregate (sand and gravel) [1] embedded in cement [1]
Why is concrete good for building?
Very strong
What does wood (composite material) consist of? [2]
Cellulose fibres [1] embedded in an organic polymer matrix [1]
What 2 things influence the properties of a polymer?
- What monomers they’re made from
- Conditions under which they are made
THINK: temp + pressure
How is low density poly(ethene) made?
Made from ethene at a moderate temperature under a high pressure
Is low density poly(ethene) flexible or rigid?
Flexible
What is low density poly(ethene) used in?
Bags and bottles
How is high density poly(ethene) made?
Made from ethene at a lower temperature and with a catalyst
Is high density poly(ethene) flexible or rigid?
Rigid
What is high density poly(ethene) used in?
Water tanks and drainpipes
Describe the structure of thermosoftening polymers
Made from lots of polymer chains held together by weak intermolecular forces
Why can thermosoftening polymers be melted and moulded?
The weak intermolecular forces break easily when melted
Describe the structure of thermosetting polymers
Made from lots of polymer chains held together by strong covalent bonds
Why are thermosetting polymers hard, strong and rigid?
The strong covalent bonds require a lot of energy to be broken
Define ‘corrosion’
Where metals react with substances in their environment and are gradually destroyed
What is is called when iron corrodes?
Rusting
What conditions does iron need to rust? [2]
- Oxygen
- Water