C9: Crude oil and fuels Flashcards
What is a hydrocarbon?
A compound containing hydrogen and carbon atoms only
What are some uses for crude oil?
Plastics
Petroleum
Medicines
Cosmetics
Is crude oil finite or infinite?
Finite
Where is crude oil found
Formed over millions of years from the remains of tiny sea creatures (namely plankton) that were buried in the mud.
What is crude oil?
A mixture of hydrocarbons
What is the general formula for alkanes?
CnH2n+2
What are alkanes?
Saturated hydrocarbons
- contain maximum possible number of hydrogen atoms, containing only single covalent bonds
What are the key properties of hydrocarbons?
Viscosity - how runny a liquid is
Volatility - how quickly a hydrocarbon reacts
Flammability - how easily a hydrocarbon combusts
Boiling point - how easily a hydrocarbon changes state
How does viscosity vary among hydrocarbons?
As chains get longer, viscosity increases
How does volatility vary with hydrocarbons?
As chains get longer, volatility decreases
How does flammability vary with hydrocarbons?
As chains get longer, flammability decreases
How does boiling point vary with hydrocarbons?
As chains get longer, boiling point increases
What are some vehicles which run on hydrocarbon fuels?
Ships
Planes
Cars
What happens during general combustion of hydrocarbons?
Carbon and hydrogen atoms react with oxygen to become oxidised
What is complete combustion?
A hydrocarbon reacting in plentiful oxygen
What is the equation for the complete combustion of hydrocarbons?
Alkane + Oxygen → Carbon dioxide + Water
e.g.
CH4 + 2O2 → CO2 + 2H2O
What is the equation for incomplete combustion of hydrocarbons?
Alkane + Oxygen → Carbon/ Carbon monoxide + Water
e.g.
CH4 + 2O → C + 2H2O
CH4 + 3O → CO + 2H2O
Why must the hydrocarbons in crude oil be separated?
In order to obtain useful products
How are hydrocarbons separated from crude oil?
Fractional distillation, it is separated into fractions, containing hydrocarbons of similar structure
Describe the process of fractional distillation
Crude oil is heated to high temperatures, until it is vaporised. It is the pumped into the fractionating column, which is hot at the bottom, and cooler at the top. The heaviest, unevaporated hydrocarbons are drained off of the bottom. The vapour the rises up the column, hydrocarbons will condense at different points within the column, upon reaching their boiling point. They are then drained out of the column
What is the pattern of hydrocarbons condensing in the fractionating column?
Long chains condense towards the bottom, short chains condense towards the top
What are fractions?
Containing a similar number of hydrocarbon atoms
What are some fractions used for and give examples?
Fuels - petrol and diesel, kerosene, heavy fuel oil, liquified petroleum gas
Feedstock - solvents, lubricants, detergents, polymers
What is the petrochemical industry?
Industries which use organic products for manufacture