Alkanes (Saturated hydrocarbons)
Chemical constitution: saturated hydrocarbons
General formula: Cn H2n+2
Characteristic suffix: -ane
| Number of carbon atoms in | Formula | Name | Alkyl group (is derived from alkane by losing one atom of hydrogen) |
| 1 | CH4 | methane | CH3 - , methyl |
| 2 | C2H6 | ethane | CH3 -CH2 - , ethyl |
| 3 | C3H8 | propane | CH3 -CH2 -CH2 - , propyl |
| 4 | C4H10 | butane | CH3 -CH2 -CH2 -CH2 - , butyl |
| 5 | C5H12 | pentane | CH3 - (CH2)3 - CH2 - , pentyl |
| 6 | C6H14 | hexane | CH3 - (CH2)4 - CH2 - , hexyl |
| 7 | C7H16 | heptane | CH3 - (CH2)5 - CH2 - , heptyl |
| 8 | C8H18 | octane | CH3 - (CH2)6 - CH2 - , octyl |
| 9 | C9H20 | nonane | CH3 - (CH2)7 - CH2 - , nonyl |
| 10 | C10H22 | decane | CH3 - (CH2)8 - CH2 - , decyl |
The alkanes are able to form a homologous series - they are differing from each other by the addition of CH2 groups.
Physical properties:
C1 - C4 = gasses
C5 - C16 = liguids
C17 and higher = solids
- colourless
- has a less density as a density of water
Structure:
1. Alkanes with straight chain
2. Alkanes with branched chain - they are able to form more than 1 structural forms it´s called constitutional isomerism
The molecules have different structures formulae but they have same formulae. That is why they have different physical properites (e.g. boiling point) but similar chemical properties.
Alkanes (Saturated hydrocarbons)
No comments found.