Isomers are compounds with the same molecular formula but different structural formula in the I/GCSE chemistry curriculum.
Isomers have different properties because they have different structures.
E.g, Boiling Point – Pentane has the highest boiling point because of its regular shape (regular arrangement = strong forces of attraction) and this allows a bigger surface area for intermolecular forces to work over and so requires more energy to overcome. Methyl Butane and Dimethyl Propane have less regular shapes, weaker intermolecular forces and therefore a lower boiling point.
Alkanes + Halogens
In I/GCSE chemistry, alkanes react with chlorine or bromine. The reaction depends on sunlight to break the halogen bonds. Methane and Chlorine react explosively and reaction speed decreases as you go down.
Cracking
Long chain alkanes can be broken down into smaller more useful alkanes and alkenes mentioned in I/GCSE chemistry. Alkenes are extremely useful because they are more reactive than alkanes and can be used to make plastics. This is Thermal Decompostion.
Cracking Conditions:
- 500°C
- Catalyst: Aluminium Oxide
End of this topic!