Topic 8 - Fuels and polymers Flashcards
What is crude oil?
A mixture of lots of different hydrocarbons
What is a hydrocarbon?
A compound made from hydrogen and carbon
Name the first 4 Alkanes
Methane, ethane, propane, Butane
What is an alkane?
A hydrocarbon made from single bonds with the general formula of CnH2n+2
What is an alkene?
A hydrocarbon made from single bonds and one double carbon bond with the general formula CnH2n
What are alkenes used for?
To make polymers
What are Alkanes used for?
Fuels
What is cracking?
When you take a long chained alkane, and break it down in to a shorter chained alkane and an alkene. You do this by using high temperatures and a catalyst.
How does cracking help match supply and demand?
You can take the long chained alkanes, which their is little demand for, and turn them into short chained alkanes that have high demand and low supply.
What does factional distillation do?
Split up crude oil into its separate hydrocarbons.
How does fractional distillation work?
The crude oil is heated until most if it has turned into gas. In the column there is a temperature gradient, where it is much hotter at the bottom than the top. The gas rises up the column until it is cool enough for it to condense. The liquid is then drained out.
What does fractional distillation rely on?
Hydrocarbons having different boiling points
What is a polymer?
A polymer is a substance made up of high average relative molecular mass made up of small repeating units called monomers
How are polymers made?
Addition polymerisation
What is addition polymerisation?
Where monomers are added together to make polymers, through high pressure and a catalyst.
Name some uses for polymers
PVC - Guttering
Polystyrene - packaging
List Advantages of using hydrogen fuel cells
No pollution
Efficient at converting chemical energy to electrical energy
Only emission is water vapour
The chemicals inside are constantly replenished, so they never run flat or need charging.
List disadvantages of hydrogen fuel cells
The production of hydrogen relies on energy from burning fossil fuels
Hydrogen needs to be stored under high pressure in thick containers
It is a gas, so more likely to leak
How is the hydrogen for hydrogen fuel cells produced?
Electrolysis of water
