C1.5 Other substances from crude oil Flashcards
In what process are long-chain hydrocarbon molecules split into smaller ones?
Cracking
Products of cracking
Petrol, paraffin and ethene
What are petrol and paraffin useful for?
Fuels
What is ethene useful for?
Plastics
What is the process of cracking?
- Heat the hydrocarbons to vaporise them
- Pass the vapour over a powdered catalyst at a temperature of around 400-700 degrees
- The hydrocarbons split apart on the surface of the catalyst
Which catalyst is used in cracking?
Aluminium Oxide
What are products of cracking?
Alkanes and alkenes (unsaturated hydrocarbons)
What is the general formula of an alkene?
CnH2n
Name a long-chain hydrocarbon molecule
Kerosene
Name a shorter Alkane molecule
Octane
Name two Alkenes
Ethene and propene
Name a difference between Alkenes and Alkanes
Alkenes have a double bond between the carbon atoms
Why are Alkenes unsaturated?
They can make more bonds, the double bond can open allowing the carbon atoms to bond with other atoms
What is one of the general representations of an alkene?
C3H6
How can you test for an alkene?
Adding bromine water. The bromine water will decolourise if an alkene is present. It will turn from orange to colourless
How is ethanol produced from ethene?
Ethene is hydrated by steam (H2O) in the presence of a catalyst. It’s cheap but non-renewable
How else can ethanol be produced?
From renewable sources through fermentation with yeast
Word equation for fermentation
Sugar => Carbon Dioxide + Ethanol
What is the material used in fermentation?
Sugar which is converted into Ethanol using yeast
Why is fermentation a good method for producing ethanol?
It is a renewable source and can be used as quite a cheap fuel
What are the disadvantages of fermentation?
The ethanol produced isn’t very concentrated so it needs to be distilled to increase its strength. It also needs to be purified
What can Alkenes be used to make?
Polymers
What is polymerisation?
The joining of many small molecules (monomers) to form very large molecules (polymers)
What are light, stretchable polymers used for?
Making plastic bags
What are elastic polymer fibres used for?
Making lycra fibre for tights
What other products are polymers used for?
Waterproof coatings for fabrics, dental polymers are used in resin tooth fillings, wound dressings, packaging, smart materials e.g. memory foam
Why are polymers hard to get rid of?
The are not biodegradable so they do not rot which leads to problems with waste disposal
What new products are being developed with polymers?
Plastic bags made of polymers and cornstarch which break down more easily and biodegradable plastics also made from cornstarch
Why will polymers become more expensive and rarer?
Crude oil resources will get used up and the price of crude oil will increase
