SC26 Bulk and Surface Properties of Matter including Nanoparticles Flashcards
What are the two types of ceramics?
Glass and Clay
How are glass ceramics made?
- By melting sand with other substances, especially metal oxides
- Then allowing the molten liquid to cool and solidify
How are clay ceramics made?
- Heating clay to high temperatures, causing crystals to form and join together.
- Often coated in a glaze, which hardens to form a hard, smooth, opaque and water proof layer
What are the properties of glass ceramics?
- transparent
- hard
- brittle
- durable
What are the properties of clay ceramics?
- opaque
- strong
- hard
- brittle
Name the two materials that don’t conduct heat or electricity?
Glass and clay ceramics
What material is a good conductor of heat and electricity?
Metal
State some properties of metals
- malleable
- ductile
- shiny
What are polymers?
Substances with high average relative formula masses
What are the properties of polymers?
- can be tailored to have specific properties
- but they are not conductors of heat and electricity
What is a composite material?
A material that consists of two or more materials with different properties
What is an alloy?
Metals that are mixed with other elements, that have different properties to the original two elements
What are two components of composite materials?
- Reinforcement
- Matrix
What is the role of the reinforcement?
Fibres/other material which make up the bulk of the composite materials
What is the role of the matrix?
Binds the reinforcement together
Name some examples of composite materials
- Fibreglass
- steel reinforced concrete
Name the reinforcement and the matrix in fibreglass
Reinforcement: glass fibres
Matrix: polymer resin
What are the properties of fibreglass?
- strong in tension
- flexible
- strong
- stiff
- lightweight
What are the reinforcement and matrix in concrete?
Reinforcement: steel
Matrix: concrete
What are the properties of steel reinforced concrete?
Strong in tension and compression, which allows reinforced concrete to be strong and slightly flexible
Why is glass used in construction?
- highly durable
- high compressive strength
- transparent
What are the uses of metal?
Used in electrical cabling and electronics due to their ability to conduct electricity
What is polymer used in?
Insulating electrical materials
What are clay ceramics used for?
Making brick, China and porcelain
Define nanoparticles
Structures only 1-100 nanometers in size, and usually contain around 100 atoms
What do the properties of nanoparticles depend on?
Their large surface area to volume ratios
What happens to the surface area to volume ratio as particles decrease in size?
It increases
What are the uses of nanoparticles?
- sunscreen: titanium dioxide blocks UV light
- Pigment in white paint in bulk
Why can nanoparticles act as catalysts?
Due to their large surface area to volume ratio
What are some possible risks of nanoparticles?
- once inside the body, they may catalyse harmful reactions
- easy to breath in
- toxic substances could bind to them
