1. Hydrocarbons – Introduction questions
What are the two elements that make up hydrocarbons?
Complete the following equation of the complete combustion of methane:
CH4 + O2  _______ + ________
3. Draw a diagram to show the electron arrangement in a molecule of methane: CH4

2. Combustion
What is needed for combustion to occur?

3. Complete and incomplete combustion
Complete combustion – there is plenty of oxygen
Water and carbon dioxide are the products.
General equation: hydrocarbon + oxygen  water + carbon dioxide
Incomplete combustion – a limited supply of oxygen
Water, carbon monoxide and carbon are the products.
General equation: hydrocarbon + oxygen  water + carbon monoxide + carbon

4. Alkanes
There are many types of hydrocarbons but most of the ones in crude oil are alkanes.
General formula: CnH2n+2
Write the formula for:
(1) methane (1C)
(2) ethane (2C)
(3) propane (3C)
(4) butane (4C)

6. Alkenes
A family for hydrocarbons that have a double bond between two carbon atoms.
General formula: CnH2n
Write the formula for:
(1) ethene (2C)
(2) propene (3C)
(3) butene (4C)

8. Testing for alkenes Bromine water is used.
An alkene will turn bromine water colourless as it reacts with the double bond.
Bromine water remains brown when added to an alkane.

9. Cracking
Allows large hydrocarbon molecules to be broken down into smaller, more useful hydrocarbon molecules.
Fractions containing large hydrocarbon molecules are vaporised and passed over a hot catalyst.
Cracking is a thermal decomposition reaction.

10. Revision Crude oil is a mixture of h___________.
What is the general formula for alkanes?
How are alkanes structurally different from alkenes?
How are the different fractions found in crude oil separated?
Name four different types of uses for the fractions found in crude oil.