Organic Reactions

Organic Reactions

This page covers:

alkenes, alcoholes, carboxylic acids, esters, hydrogenation, homologous series, fermentation,

Key Words

Alkenes – hydrocarbons, they have a double carbon-carbon, C=C, bond in their chain. They are unsaturated.

  • The first four alkenes are ethene (two carbon atoms), propene (three carbon atoms), butene (four carbon atoms), pentene (five carbon atoms).
  • Alkenes combust completely in a large amount of oxygen to product water and carbon dioxide.
  • Alkenes react via additon reactions. The double bond opens up to create a single bond. Alkenes can react with Halogens this way.
  • Mix alkenes with steam and them pass it over a catalyst to form alcohols.

Hydrogenation – hydrogen reacts with double-bonded carbons to create a single bond with a catalyst.

Catalyst - a substance that speeds up a reaction without being used up in the reaction itself.

Homologous series – a group of chemicals that react in a similar way, they have the same functional group.


  • Contain an -OH functional group.
  • They are flammable.
  • Their solutions have a neutral pH.
  • They react with sodium.
  • They can be oxidised.
  • Methanol and ethanol are used as solvents.
  • Ethanol is used as fuel in spirit burners, it’s clean and non-smelly.
  • Ethanol is found in alcoholic drinks, it’s made by fermentation.

Carboxylic Acids

  • Contain -COOH as a functional group.
  • React with carbonates to produce a salt, water and carbon dioxide.
  • Can dissolve in water. They ionise and release H+ ions making an acidic solution.


  • Contain -COO- as a functional group.
  • Formed from alcohol and carboxylic acid with an acid catalyst.


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