C9 Crude Oil And Fuels Flashcards
What is the definition of a hydrocarbon?
A molecule comprised of only hydrogen and carbon atoms
What is the general formula of an alkane?
C(n) H(2n+2)
What type of molecules are alkanes?
Saturated
What makes alkanes saturated?
They contain only C-C single bonds
State the first four alkanes and their structures
Methane (CH4)
Ethane (C2H6)
Propane (C3H8)
Butane (C4H10)
What is the viscosity of a liquid?
The “thickness of a liquid”
High viscosity liquids flow slower
Describe how the size of a hydrocarbon affects its viscosity
As the size of the hydrocarbon chain increases, so does the viscosity
Describe how the length of a hydrocarbon chain affects its flammability
The shorter the hydrocarbon chain, the greater its flammability
Describe how the length of a hydrocarbon chain affects its boiling point
The shorter the hydrocarbon chain, the lower its boiling point
What are the products of complete combustion?
Carbon dioxide and water
What are the products of incomplete combustion?
Carbon monoxide and water
Why does incomplete combustion occur?
Due to a limited oxygen supply
What is combustion?
Burning in oxygen (to release energy)
Describe the process of fractional distillation of crude oil
Firstly the crude oil is heated to a high temperature to boil it. The crude oil vapour is fed into the fractional distillation column, which is hotter at the bottom, and cooler at the top. The vapour rises up the column, and hydrocarbons condense when they reach their boiling point, and the liquid fractions are then removed. The remaining hydrocarbons continue moving up the column and condense when they reach their boiling points. Very short chain hydrocarbons have low boiling points and don’t condense, and are removed from the top of the column as gases
What are Fractions?
Hydrocarbon chains with a similar number of carbon atoms
What Hydrocarbons fractions are used to fuel cars?
Petrol and Diesel
What Hydrocarbon fraction is used to fuel jets?
Kerosene
What Hydrocarbon fraction is used to power ships?
Heavy fuel oil
What Hydrocarbon fraction is used in camping stoves?
Liquified petroleum gas
What is a feedstock?
A chemical used to make other chemicals
What are some uses of hydrocarbons as feedstock?
- Lubricants
- Solvents
- Detergents
- Polymers
Where is crude oil found?
In rocks
Name the 2 key features of alkanes
- They have single bonds between carbon atoms
- They have the formula C(n) H(2n+2)
What type of bond is between carbon atoms in an alkane?
A single covalent bond
Why don’t long chain hydrocarbons make good fuels?
As they aren’t very flammable in comparison to short chain hydrocarbons
What is the purpose of Cracking?
To make long chain hydrocarbons into shorter and more useful ones, that have a higher demand
What are the 2 methods of cracking?
Catalytic and Steam
Describe the conditions for catalytic cracking
High temperature and a catalyst
Hydrocarbon in a vapour
Describe the conditions for steam cracking
High temperature and steam
Hydrocarbon in a vapour
What type of bond is between carbon atoms in an alkene?
A double bond
What is the general formula for the structure of alkenes?
C(n) H(2n)
Why are alkenes useful?
They’re used to make polymers and as starting materials to make other chemicals
Compare the reactivity of alkanes with alkanes
Alkenes are more reactive
What is the solution used to test for alkenes?
Bromine water
Describe the test for Alkenes
Shake the alkene inside bromine water, which will turn from orange to colourless
colourless not clear
Which molecule releases more energy per mole when burnt, alkenes or alkanes?
Alkanes
What type of reaction is involved in cracking?
A thermal decomposition reaction
What type of hydrocarbon is an alkane?
A saturated hydrocarbon
What type of hydrocarbon is an alkene?
An unsaturated hydrocarbon
What kind of carbon - carbon bond is there in an unsaturated hydrocarbon?
A double bond
