Structures and Properties of Alcohols
- Alcohols contain the functional group -O-H. If one hydrogen atom from each alkane molecule is replaced with an -O-H group, we get a homologous series of alcohols.
- First three members of this series and methanol, ethanol and propanol.
- A structural formula shows which atoms are bonded to each carbon atom and the functional group. The structural formula of ethanol is CH3CH2OH.
- Good solvents
- Burn easily
- mix with water to produce a neutral solution- covalent molecule = no ions!
- oxidised easily- potassium dichromate- carboxylic acid.
Structures and Properties of Carboxylic Acids
- Formed by the the oxidation of alcohols with potassium dichromate
- Carboxylic acids react with metal carbonates producing a salt plus water and carbon dioxide.
Ethanoic acid + sodium carbonate = sodium ethanoate + water + carbon dioxide
- Carboxylic acids have the functional group -COOH.
- The first three members of the carboxylic acids are methanoic acid, ethanoic acid and propanoic acid. Their structural formule are HCOOH, CH3COOH and CH3CH2COOH.
- Mixed with water = acids
- react with metals
Carboxylic acid + Alcohol + Ester
Structures and Properties of Esters
- Esters are formed when an alcohol with a carboxylic acid react in the prsence of an acid catalyst.
Ethanoic Acid + Ethanol =( sulfuric acid catalyst)= Ethly ethanoate + Water
- They have a functional group of -COO-. If the H atom in the -COOH group of a carboxylic acid is replaced by a hydrocarbongroup the compound is an ester.
- Ethyl ethanoate has the structural formula CH3COOCH2CH3.
Esters are used in flavourings and perfumes as they have a very distinctive smell.