Chapter 5 - Products From Oil Flashcards
How can cracking be carried out
- Heating a mixture of hydrocarbon vapours and steam to a very high temperature
OR - Passing hydrocarbon vapours over a hot catalyst
What does cracking produce
Alkanes and alkenes
Why are alkenes more reactive than alkanes
They have a double bond
How can you test for an alkenes
Bromine water turns from orange to colourless
What are plastics made from
Polymers
What are the small molecules used to make polymers called
Monomers
What is the reaction called to make a polymer
Polymerisation
What happens in a polymerisation reaction
The double bond in each ethene molecule becomes a single bond
When are light sensitive polymers used
Sticking plasters to cover wounds so the plasters can be easily removed.
What are hydrogels
Polymers that can trap water and have many uses including dressings for wounds
What are shape memory polymers
They change back to their original shape when temperature or other conditions are changed. An example of a smart polymer is a material used for stitching wounds that changes shape when heated to body temperature
Why may fibres of fabrics be coated with polymers
To make them waterproof and breathable
Why is biodegradable plastic good for the environment
Microorganisms break down biodegradable plastics. These plastics break down when in contact with soil
Why do plastics from non-biodegradable polymers have cornstarch mixed into the plastic.
Microorganism break down the cornstarch so the plastic breaks down into very small pieces that can be mixed with soil or compost
How can ethanol be produced
By the fermentation of sugar from plants using yeast. Enzymes in yeast cause sugar to convert to ethanol D and carbon dioxide
