R-ATCHE-21

Organic Hydrocarbons: Combustion $\to CO_{2(g)} + H_{2}O_{(l)}$

Key Vocab:

• Aliphatic - straight chains

• Alicyclic - rings

• Aromatic - benzenes and the likes

• Alkanes - single bonded C's - saturated.

• Alkenes - double bonds - unsaturated

  • Recall we must give a number for the double bond if necessary. i.e. for ethene its fine (theres only one place), for butene it can be either but-1-ene, or but-2-ene (also have to consider cis-trans isomerism).

How to represent organics?

• Structural formula
• Molecular formula
• Semi-structural/condensed formula

In an exam you must draw H's!

Structural isomers: when you can rearrange a molecule. i.e. different structural formula, same molecular formula

Geometric/cis-trans isomers: Due to the nature of double bonds, the position is fixed. Hence, compounds containing double bonds can have geometric isomerism, where the way the molecule is locked can produce structural isomers that are not identical but only because the double bond is locked. i.e. the spacial orientation of the structural formula is different, but both molecular and structural formula are the same. (??? norrie moment)

Don't write the number if you don't have to!

Properties

• Non polar molecules - Dispersion forces
  • WEAK - Small number of electrons
  • STRONG - Large number of electrons, i.e. larger molecular mass
  • Insoluble in $H_{2}O$.

Very important

Dispersion forces states of matter

Low MP/BP

• Gasses: 1-4 Carbons
• Liquid: 5 - ?
• Solid: very long chain, i.e. waxes

Observations

• Common test for double bond:
  • $Br_{2(aq)}$ (Bromine water) is rapidly decolourised

Backlinks

Recent pages

None found yet.