Chemistry GCSE Edexcel - C3

Alcohols, Carboxylic Acids and Esters

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  • Created by: Tiula
  • Created on: 24-05-10 11:02

Alcohols - Properties

  • Alcohols have a functional group -OH
  • Their general formula is CnH(2n+1)OH
  • The first four alcohols are: methanol, ethanol, propanol and butanol

Alcohols are:

  • flammable (burning to produce carbon dioxide and water)
  • volatile (they evaporate easily)
  • miscible with water (only the first three)
  • toxic
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Alcohols - Uses

The carbon chain allows alcohols to mix with oils and the -OH functional group allows them to mix with water. This means that they are very good solvents.

  • used in the solvents for perfumes and aftershaves
  • meths (ethanol, methanol and blue dye) is used to clean brushes and as a fuel
  • ethanol is used in spirit burners
  • 'gasohol' is used in some countries as a greener alternative to petrol - ethanol and petrol mixed together.
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Carboxylic Acids - Properties

  • Carboxylic acids (organic acids) have a functional group -COOH
  • First four are methanoic acid, ethanoic acid, propanoic acid and butanoic acid

Carboxylic acids:

  • are miscible with water (but the longer the chain, the less miscible it is)
  • are miscible with alcohol
  • react like most acids, forming salts
  • are corrosive
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Carboxylic Acids - Uses

  • ethanoic acid is in vinegar
  • citric acid is in lemons and oranges, used in fizzy drinks and in kitchen descaler
  • aspirin
  • to make esters
  • to make soaps and detergents
  • good solvent (but often not chosen as it makes the solution acidic)
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Esters - Properties

  • Esters have a functional group -COOH-
  • formed from an alcohol and a carboxylic acid:
    • alcohol + carboxylic acid => ester + water

Esters:

  • smell nice
  • mix with alcohol but not water
  • are colourless liquids with low boiling points
  • are volatile
  • are flammable
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Esters - Uses

  • perfumes
  • flavourings and aromas
  • ointments (e.g. Deep Heat)
  • solvents in paint, ink, glue and nail varnish remover

SAFETY ISSUES

  • fumes can irritate mucus membranes in the nose and mouth
  • very flammable
  • toxic in large doses
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Comments

Lucy

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the audio is crazy but the actual notes are fantastic :) x

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