C1.5 Other useful substances from crude oil Flashcards
Why are hydrocarbons cracked and what are some of the products useful as?
- To obtain smaller, more useful molecules
- Fuels
What is the process of cracking? (HCs= hydrocarbons) (2)
- HEATing the HCs to vaporise them
- VAPOURS are passed over HOT CATALYST or mixed with steam and heated to a v. high temp
Once the HC vapours are mixed with steam, why are they heated to a very high temperature?
So that thermal decomp. reactions can then occur
What are the two products of cracking and their general formula?
- Alkanes CnH2n+2
- Unsaturated HCs called alkenes CnH2n
What is the test for an unsaturated bond?
Bromine water will turn from orange to colourless if an unsaturated (double) bond is present
What is used to make polymers? Name two polymers that it could make
- Alkenes
- Polyethene, polypropene
How are polymers formed? (1)
Many small molecules join together to form very large molecules (polymers)
What’s the ‘posh’ word for a small molecule (in relation to polymers)?
Monomer
Polymers have many useful applications and new uses are being developed. Name up to 5 uses
- Packaging materials (clingfilm)
- Waterproof coatings (coats)
- Dental polymers (fillings)
- Wound dressings
- Hydrogels (soft contact lenses/disposable nappy liners)
What is the environmental impact of using polymers?
Not biodegradable, not broken down by microbes
go to LANDFILL
What are plastic bags now being made from? Why?
- Polymers and cornstarch
- So they break down more easily
Biodegradable _____ made from _____ have been developed
Biodegradable PLASTICS made from CORNSTARCH have been developed
How can ethanol be chemically (not naturally) produced? (3)
- By hydration of ethene
- With steam
- In the presence of a catalyst
How can ethanol be produced naturally? What is the word equation for this?
- By fermentation with yeast
- Using renewable resources
- sugar —-> carbon dioxide + ethanol
