Products from oil Flashcards
(36 cards)
What is cracking?
The breaking down of long-chain hydrocarbons (e.g. heating oil) into smaller ones (e.g. petrol)
Why do we crack long-chain hydrocarbons?
The shorter chain hydrocarbons are more useful to use for fuel
What happens when diesel, a long molecule is cracked?
Diesel –>(cracking) petrol + paraffin + ethene for plastics
What type of reaction is cracking?
Thermal decomposition
The breaking down of molecules by heating them
What is the process of cracking? (method)
1- Heat long-chain hydrocarbon
2- Vapour passed over a powdered catalyst at about 400-700 degrees celsius
3- Aluminium oxide is used as the catalyst
4- Long-chain products split apart (crack) on the surface of the specks of catalyst
5- Most of the products are alkanes and alkenes
Show the cracking of kerosene…
Vaporised kerosene –>(Aluminium oxide catalyst)–> octane + ethene
What is the test for discovering if a hydrocarbon is an alkane or an alkene (saturated or unsaturated)?
Bromine water test
- Bromine water is orange
- Hydrocarbons are colourless
- If the hydrocarbon is unsaturated then the bromine water when added will turn colourless, using up the free bonds until it becomes saturated
What are the properties of alkanes?
- Saturated
- No space for more hydrogen atoms
- Single bonds
What are the properties of alkenes?
- Unsaturated
- Carbon=carbon double bond
- Double bond can be broken to add more hydrogen atoms
What is a monomer?
A small molecule used to make a polymer
What is an addition polymer?
A polymer made up of similar monomers
What are the processes involved from crude oil to polymerisation?
Crude oil –> Fractional distillation –> Cracking –> Polymerisation
What does the monomer ethene form?
An addition polymer
Polythene (Poly(ethene))
What is Poly(tetrafluoroethene) and what are its uses?
- Monomer= C2F4
- Inflammable, used for non-stick pans
What is the monomer of Poly(chloroethene)?
C2H3Cl
Why is ethene the smallest unsaturated hydrocarbon?
There has to be at least 2 carbon atoms to make a double bond with the ability to have free space for hydrogens
How can we produce ethanol using ethene?
By reacting ethene with steam in the prescence of a catalyst
Hydration
What are the benefits and drawbacks of using ethene to produce ethanol?
- Cheap, not much wasted
- Ethene produced from crude oil which is non-renewable and a fossil fuel (will become expensive as it runs out)
What is ethanol used for?
Fuel for cars
chemical name for alcohol C2H5OH
What are the benefits of ethanol?
- Renewable
- Clean burning
- Carbon neutral
How is ethanol made from sugar?
- Sugar dissolved in warm water
- Add yeast
- Causes fermentation reaction
- Yeast converts sugar into ethanol
Sugar (glucose) –>(yeast) ethanol + carbon dioxide
What are the advantages of using fermentation to make ethanol?
- Doesn’t require electricity
- Renewable source
- Needs lower temperatures and simpler equipment
- Can be used as quite a cheap fuel
- Sugar is a major crop grown all over the world and could provide more income to LICs who grow it
What are the disadvantages of using fermentation to make ethanol?
- Gives off carbon dioxide as a by-product
- This greenhouse gas contributes to global warming
- Forests may have to be destroyed to make space for sugar plants
- Loss of crop land which could have been used for food
- Not very concentrated so would have to be distilled
- Needs to be purified
What are the advantages of hydrating ethene to make ethanol?
- No by-products
- Continuous process
