Lecture notes - Cell And Molecular Biology (Hydrocarbons)

Hydrocarbons 30/09/19
- Made up of Hydrogen and Carbon
- Provide energy – C12 is the backbone of life
- Anything with C12 is organic

The octet rule means that atoms always want 8 e- in their outer shell

C12 has 4 valance e- therefore needs 4 more via covalent bonding.

(Mostly A level stuff so just a recap)

Shapes of hydrocarbons:
Alkanes = the simplest group of Hydrocarbons.
CH4 = Tetrahedral:
Each C12 is bonded to 4 H2 atoms

Tb increases as you increase the hydrocarbon chain. (Length of
the chain determines physical properties.)

CH4 (methane) → CH3 (methyl)
C2H4 = Planar: When naming, list substituents in alphabetical order (i.e. ethyl
before methyl when naming.)




Alkane = C-C
Increasing the bond number reduces the size
Alkene = C=C of the molecule.
Alkynes = C≡C

(As with A level chemistry, with alkenes, ‘=’ position determines the name, e.g. 1-Butene or 2-Butene
or But-1-ene, 2-ene, 3-ene, etc.)

Cyclo and Benzene = Rings

Isomers:
‘Iso’ = equal therefore isomers of hydrocarbons mean equal no. atoms of same element.

Different structures:

- Structural
- Cis/trans (E-Z)
- Optical (Enantiomers)