7.1 Hydrocarbons, Fractional Distillation, Crude Oil Flashcards
(20 cards)
From where is crude oil obtained?
It is a finite resource found in rock.
Crude oil is formed from the remains of plankton buried in mud that was heated under high pressure for millions of years.
What is crude oil?
A mixture of hydrocarbons.
Crude oil is primarily composed of various hydrocarbons.
What are hydrocarbons?
Molecules made of hydrogen and carbon atoms only.
What are alkanes?
A type of hydrocarbon with the general formula CnH2n+2.
What is a homologous series?
A group of organic molecules with the same functional group where each successive member differs by CH2.
What is a functional group?
An atom or group of atoms on an organic molecule that gives it characteristic chemical reactions.
Name the first four alkanes.
- Methane
- Ethane
- Propane
- Butane
Give the molecular formula of propane.
C3H8.
What is fractional distillation?
A process used to separate mixtures of substances with different boiling points.
What are the steps involved in fractional distillation?
Crude oil is mostly vaporised, vapours rise up the fractionating column and cool down. They condense at different points on the column depending on their boiling points.
What is a fraction?
Fractions are mixtures of hydrocarbons with similar numbers of carbon atoms.
What can fractions be processed into?
Fuel and feedstock for the petrochemical industry.
Name five fuels we obtain from crude oil.
- Petrol
- Diesel
- Kerosene
- Heavy fuel oil
- Liquefied petroleum gases
What products are obtained from the petrochemical industry?
- Solvents
- Lubricants
- Polymers
- Detergents
Name three properties of hydrocarbons that depend on their size.
- Boiling point
- Viscosity
- Flammability
How does molecular size affect hydrocarbon boiling point?
The bigger the molecule, the higher the boiling point.
How does molecular size affect hydrocarbon viscosity?
The bigger the molecule, the more viscous (thicker) it is.
How does flammability change with the length of an alkane?
The bigger the molecule, the less flammable it is.
What is the main purpose of combustion of hydrocarbons?
To release energy.
What happens to the atoms of hydrocarbons during combustion?
The hydrogen is oxidised to form water and the carbon is oxidised to form carbon dioxide.
