Organic Chemistry

go back

Hydrocarbons

• Only hydrogen and carbon
• Aliphatic: Straight chains
• Alicyclic: rings
• Aromatic: Benzene
• Combustion $\to C{O}_2+H_{2}O$
• Alkanes: single bonded Carbon atoms
  • Saturated Naming is based on longest chain

1. Meth
2. Eth
3. Prop
4. But
5. Pent
6. Hex
7. Hept
8. Oct

in an exam you must draw H’s

IUPAC: only number stuff if you need to Structural Isomers: different arrangements, same formula

Halogen Substitution

• Basically a halogen just replaces an H atom

Alkanes

• Insoluble in water

Alkenes

• Double bonds between carbon atoms - unsaturated
• add a prefix to the number of double bonds
• Shake with aqueous bromine (bromine water), it will rapidly decolourise

Benzene

• Aromatic hydrocarbon
• $C_6{H}_6$
• Strangely stable
• Thought to be alternating single and double bonds
  • But Double bonds are stronger than single bonds
• It kinda looks like a nut
  • Like, the one on a screw
• Delocalised electrons within molecule
  • thus cannot conduct electricity
• The electrons move around in the molecule, contributing to its stability

Carboxylic acids

• Products of oxidation of alcohols
• Organic acids
• Functional group is $OO{H}^{-}$, attached to end carbon
  • Double bond between Carbon and Oxygen group
  • E.g. ethanoic acid
• -anoic acid suffix
• Default start of chain is the acid functional group

Aldehyde

• Double bonded oxygen on the end of a chain
• Functional group of $O{H}^{-}$
• Slightly polar
• Medium m.p. - b.p.??
• not particularly solube
• Hydrogen bonding with water
• -al suffix

Ketones

• Similar to aldehydes
• But double bonded oxygen is in middle of chain
  • Put number between -one and prefix
• Excellent solvent for stuff other than water
• -one suffix (pronounced like own)

Alcohols

• $O{H}^{-}$ functional group somewhere on the chain
• -ol suffix
• Hydrogen bonding between molecules
  • Relatively high m.p. and b.p.
  • Soluble in water
    • Separate by distillation
• Oxidation (not combustion)
• Primary: carbon bonded to functional group is bonded to only 1 other carbon atom
• Secondary: carbon bonded to functional group is bonded to only 2 other carbon atoms
• Tertiary: carbon bonded to functional group is bonded to only 3 other carbon atoms
• tertiary do not oxidise YAY!
• form esters (later) (polyesters)
  • Alcohol and acid organically joining together with oxygen
• Reacts with sodium
  • $2C{H}_{3}C{H}_{4}O+2Na\to H_{2(g)}+2N{a}^{+}[C{H}_{3}C{H}_{4}O{]}^{-}$
  • -oxide suffix
  • in this case, eth-oxide
  • Primary > secondary > tertiary in terms of reactivity with sodium
• Hydration creates alcahols
• Fermentation: yeast respire without $O_2$ to give alcohol and $C{O}_2$
  • 13% $\to$ distillation

Esters

• Acid + alcohol creates an ester and water
• Double bonded oxygen on carbon atom
• Can’t form hydrogen bonds with itself
  • lower mp/bp than alcohol/acid
  • Can form hydrogen bonds with water
• Warm ester reacts with sulphuric acid, it reforms an acid and alcohol
• Warm ester and $O{H}^{-}$ gives alcohol back and acid salt ion

Amides

• Functional group is $N{H}_2$
• Primary - not the same as alcohols
• Hydrogen bonding
  • Nitrogen has less electrons, thus weaker IMFs than alcohols

Moles and Pressure, volume and temperature

• Pressure is proportional to temperature (gas) and number of moles of gas
• It is inversely proportional to volume
• $PV=nRT$