1. Alkanes
Organic Chemistry

2. Hydrocarbons There are around 6 million known carbon compounds.
Because there are so many chemists grouped them by similar structures.
One of the simplist type of organic compound is the hydrocarbon.
A hydrocarbon contains carbon and hydrogen only.
The hydrocarbons we will be looking at can be divided into two groups:
Saturated – only contain single bonds - Alkanes
Unsaturated – containes one or more double bond - Alkenes

3. Alkanes Carbon has a valency of 4 – can make 4 single bonds.
In Alkanes all carbons make 4 single bonds.
Simplest alkane – methane.

4. Alkanes CnH 2n+1 Prefixes
Meth 1
Eth 2
Prop 3
But 4
Pent 5
Hex 6
The ending „ane“ tells you it is in the alkane family.
The prefix tells you the number of carbon atoms in the chain.

5. Patterns in Alkanes
As the length of the chain increases, the strength of the weak forces between the molecules increases (intermolecular forces). This results in increased boiling point with increased chain length.

6. Burning Alkanes All alkanes burn very well.
They burn very exothermically – they give out lots of energy.
Alkanes make good fuels.

7. Burning Alkanes
When alkanes burn in air the products are carbon dioxide and water vapour.

8. Uses of Alkanes

9. Activity
Complete worksheet
Extension – complete questions on page 290