C1.4 Crude Oil And Fuels Flashcards
What is crude oil?
A fossil fuel that comes from the earths crust and is one of the most important substances in the world.
It’s s mixture of hundreds of compounds. Including alkanes
What can we use crude oil for?
Transport
Heating
Generating electricity
Making plastics
What are alkanes?
Made up of single chain carbon atoms with hydrogen atoms bonded to them. Eg.
H
|
H-C-H
|
H
What’s the formula for alkanes?
C(n) H(2n+2)
Are single carbon bonds (alkanes) saturated or unsaturated?
Saturated
Single = Saturdated
Sssssssss
Are double carbon bonds saturated or unsaturated?
Unsaturated
Names the first 10 alkanes.
Methane Ethane Propane Butane Pentane Hexane Heptane Octane Nonane Decane
Define volatility.
How easy something changes like evaporation to condensation
Define viscosity
How runny or thick a substance is
Boiling point, volatility, flammability, viscosity and colour. State whether short or long chains have the highest one of these.
Short chain molecules:
More volatile
Mor flammable
Light in colour
Long chain molecules:
Higher boiling point
More viscous
Dark in colour
Name a substance that would be at the top and bottom of the fractioning column.
Top - petrol
Bottom - bitumen
Are small molecules at the top or bottom of the fractioning column?
Top
Are longer chains at the top or bottom of the fractioning column?
Bottom
Describe and explain how the fractions are separated in a fractioning column. (6)
Crude oil is a mixture and the oiled heated. Then you vaporise the crude oil which makes it a vapour, it then enters the fractioning column and is gradually heated and very slowly the temperature rises. The hydrocarbons which are small chain molecules have a low boiling point and rise to the top where it then leaves the tube and forms a very pale colour. The long chain molecules have a high boiling point so stay at the bottom of the column. The substances all separate into different fractions and then you can collect the different substances.
When does complete combustion happen?
When there’s enough oxygen
What’s the equation for complete combustion?
CH4 + 2O2 -> CO2 + 2H2O
(Doesn’t have to be methane)
Hydrocarbon + oxygen -> carbon dioxide + water
What’s oxidisation?
When you add oxygen to a chemical reaction and oxides are formed.
What tests for the presence of water?
Blue cobalt paper
It turns pink of there is water
When does incomplete combustion happen?
When there’s not enough oxygen
What’s the equation for incomplete combustion?
Hydrocarbon + oxygen -> carbon monoxide + carbon + water
What’s bad about carbon dioxide?
It’s a greenhouse gas which means it causes global warming by trapping heat from the sun within the earths atmosphere.
What’s carbon monoxide?
And odourless, tasteless, poisonous gas. It’s very deadly of you are with it in an enclosed space.
Therefore if it’s produced its harmful to organisms
What does carbon from incomplete combustion do?
Aka particulates. It contributes to global dimming and damages our cells contributing to cancer.
Why is sulphur dioxide bad if produced?
Reacts with water causing acid rain
C9H20 + 14O2 -> ???
9CO2 + 10H2O
How do we reduce the amount of particulates produced?
Use filters
What are catalytic converters?
Get rid of nitrogen oxide and carbon monoxide.
Made up of platinum, rhodium and palladium. Nitrogen oxide molecules turn into nitrogen and oxygen. Carbon monoxide reacts with oxygen and makes carbon dioxide and water. Only works at high temps. Very large surface area.
How would you get rid of sulphur?
Desulphurisation
The gas passes through CaO or CaCO3 which reacts with sulphur dioxide and produces gypsum which is used in plasterboards (harmless)
What’s a biofuel?
Fuels made up of animal or plant products
What’s biodiesel?
A fuel from plant oils
What’s biogas?
A fuel made from animal waste
What’s ethanol?
A biofuel made by fermenting sugar from sugar cane or sugar beet
What does carbon neutral mean?
When plants grow they remove carbon dioxide from the atmosphere. This is photosynthesis. When we burn these plants, the co2 is returned. There is no change in the amount of carbon dioxide in our atmosphere.
What are some advantages of biodiesel?
Breaks down quickly
Not that harmful if spilt
Renewable
Carbon neutral
Waste products are useful
A Diesel engine doesn’t need to be modified in order to run off biodiesel
Produces less sulphur dioxide than regular diesel
What are some disadvantages of biodiesel?
Uses large areas of land to grow the crops - food prices increase - destroys habitats
Can become sticky at high temps
Can freeze at low temps
Harvesting, processing the oil and transporting it all uses energy which releases carbon dioxide into the atmosphere
What are the advantages of using hydrogen as a fuel?
Produces a lot of energy
Very clean - water is the only product
We can obtain hydrogen from water by electrolysis
What are disadvantages of using hydrogen as a fuel?
Electrolysis requires energy and is expensive
It’s a gas which isn’t very practical or safe in a car
Other than sulphur dioxide, what else causes acid rain?
Nitrogen oxide
What are particulates?
Tiny solid particles containing carbon and unburnt hydrocarbons
