Meterials Flashcards
What is cracking?
When large hydrocarbon molecules (alkanes) are broken down into smaller, more useful ones, some of which are unsaturated (alkenes).
Why is cracking necessary?
It helps to match the supply of fractions with the demand for them. The supply of fuels is improved.
How are polymers formed? (1)
A polymer is made up of lots of small molecules joined together called monomers.
What is a polymer? (1)
A polymer is a useful chemical made of many repeating units.
What is an addition reaction?
An addition reaction is an organic reaction where two or more molecules combine to form a larger one.
What is the general formula for alkane?
CnH2n+2
What is the general formula for alkene?
CnH2n
What is the structure of monomer used to make the addition polymer?
Small unsaturated monomers join up by the opening of the double bond allowing them to join up to form a long carbon chain.
what are the problems with polymers: availability of starting materials
Persistence in landfill sites, due to non-biodegradability greenhouse gases and toxic gases produced during disposal by combustion.
What are 3 disadvantages with polymers?
Cannot withstand very high temperature as all plastics melt down very soon as compared to metals.
The strength to size ratio of polymer is less while for metals is more.
Cannot be machined easily and limited speed for machining for it.
Heat capacity of polymer is very less so cannot be used in heat applications.
What are 3 advantages of recycling polymers?
Environmental conservation and protection Reduce consumption of energy Reduce air and water pollution Global warming mitigation Limit waste in landfills
What are 3 disadvantages of recycling polymers?
More pollution and energy consumption
Result in pollutants
Increased processing cost and low-quality jobs
Require stricter and more stringent implementation
Good products are not guaranteed
Give a list of units ranging from cm downwards?
mm, μm, nm, pm, fm
How are properties of nanoparticulate materials related to their uses?
Nanoparticles are so small that they can enter biological tissue.
They can be mixed into other materials to form composite materials with improved properties. Nanoparticulate materials are used in some paints, cosmetics and sunscreens.
What are the risks associated with noanoparticulate materials?
Nano particles are extremely small making them able to to go in your skin and cells.
What are the properties of clay (appearance, melting point, malleable or brittle, ability to conduct electricity and ability to conduct heat)
Opaque High Brittle Poor Poor
What are the properties of glass (appearance, melting point, malleable or brittle, ability to conduct electricity and ability to conduct heat)
Transparent High Brittle Poor Poor
What are the properties of metals (appearance, melting point, malleable or brittle, ability to conduct electricity and ability to conduct heat)
Shiny High Malleable Good Good
What is a life cycle assessment?
A LCA can be worked out to work out the environmental impact of a material. It is usually carried out as a comparison between different materials to see which has the lowest environmental impact.
What are some advantages of a life cycle assessment?
Compare two products and to select the product that has the lowest impact on the environment.
It prevents reducing the environmental impact in one stage while increasing the impact at other stages of the life cycle.
What are some advantages of a life cycle assessment?
LCA studies depend on assumptions and scenarios, as LCA assesses the real world in a simplified model. Studies can also have different scopes, so one study may leave out impacts or processes that another study has included.
What are you comparing these scores to?
What unit is... A strand of dna measured in a sodium atom a molecule of water an ant sodium nucleus proton
m pm nm mm fm am
What bond does an alkene have?
C=C
What is an alkane?
A saturated hydrocarbon
