Products from Oil Flashcards
What is cracking?
The process of breaking large hydrocabons down into smaller hydrocarbons
How can cracking be done?
In two ways:
- By heating a mixture of hydrocarbon vapours and steam to a very high temperature
- By passing hydrocarbon vapours over a hot catalyst
What happens during cracking?
Thermal decomposition reactions produce a mixture of smaller molecules.
These smaller molecules are alkanes and alkenes
What are alkanes with smaller molecules useful for?
Fuels
What is the general formula for alkanes and what are they?
Saturated hydrocarbons
C<em>n</em>H2n+2
What is the general formula for alkenes and what are they?
Unsaturated hydrocarbons - they contain a double bond
CnH2n
What can bromine water be used to test for?
Alkenes - they turn it from orange to colourless
How can different mixtures of alkenes and alkanes be produced?
By using different hydrocarbons
By changing the conditions of the reaction
What are plastics made from?
Polymers
What are polymers?
Very large molecules made from lots of the same very small molecule (monomers) joined together
How are polymers made?
Polymerisation (the reaction of monomers to make polymers)
What happens during the polymerisation reaction to produce polymers?
The double bond in each of the alkenes are broken and used to join monomers together in long chains
Draw a diagram showing the polymerisation of ethene

What is formed when propene is polymerised?
Poly(propene)
Give some examples of uses of plastics
- Bags
- Bottles
- Containers
- Toys
- Furniture
Why can polymers be made from alkenes but not alkanes?
Alkanes are saturated and do not contain a double bond.
This means that it cannot be broken and used to join monomers/molecules together to form long chains
Give some examples of new and useful polymers
- Polymers to replace mercury in dental fillings
- Light-sensitive polymers to be used in plasters to cover wounds so plasters can be easily removed
- Hydrogels are polymers that can trap water and have many uses including dressings for wounds
- Shape-memory polymers change back to their original shape when temperature/other conditions are changed. Can be used as stitches that revert back to their original shape when heated to body temp.
- Fibres used to make fabrics can be coated with polymers to make them waterproof + breathable
- Plastic used to make drinks bottles can be recycled to make polyester fibres for clothing, pillow filling, and duvets
What are smart polymers?
Polymers that change in response to their environment
E.g. shape-memory polymers
Complete the sentence:
Many polymers are not…
…biodegradable
What does biodegradable mean?
Materials that can be broken down by microorganisms
What are the drawbacks of non-biodegradable plastics?
- Unsightly
- Can harm wildlife
- Take up space in landfill sites
How are plastics made more environmentally friendly?
- Biodegradable - microorganisms break them down on contact with soil
- Non-biodegradable plastics have cornstarch added. Microorganisms break down the cornstarch, also breaking down the plastic into smaller pieces that can be mixed with soil/compost
- Biodegradable plastics can be made from plant material. E.g. polymer made from cornstarch that’s used as food packaging
- Can be recyled - however many different types so sorting is hard
What is the formula for ethanol?
C2H5OH
How can ethanol be produced?
Fermentation or hydration
Describe how fermentation is used to produce ethanol
- Sugar can be fermented using yeast
- The enzymes in the yeast convert the sugar into ethanol + CO2
- This method is used to make alcoholic beverages
Describe how hydration is used to produce ethanol
- Can be made through the hydration of ethene
- The ethene is obtained from crude oil by cracking
- It is then reacted with steam at a high temperature in the presence of a catalyst
What are the advantages and disadvantages of producing ethanol using fermentation?
- It uses a renewable resource, sugar from plants
- Is done at room temperature
HOWEVER:
- Only produces small amounts (batch production)
- Produces dilute, aqueous solution of ethanol, meaning it must be seperated from the solution using fractional distillation to give pure ethanol
- Is slower
- Produces CO2 (albeit small amounts)
What are the advantages and disadvantages of producing ethanol using hydration?
- Can run continuously
- Produces pure ethanol
HOWEVER:
- Uses a non renewable resource, crude oil
- Requires a high temperature (and high energy)