C7 - Topic 1 (Organic Chemistry) xD

Notes on the deifferent Organic families...

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  • Created by: Namita
  • Created on: 17-05-12 12:55

Topic 1 - Organic Chemistry

The next few cards will include information on the following:

  • Alkanes
  • Alcohols
  • Carboxylic acids
  • Esters
  • Making Esters in detail
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Alkanes

General facts about Alkanes

  • Alkanes are a family of hydrocarbons
  • The alkane formula is: CnH2n+2

Properties of Alkanes

  • bigger alkane molecule --> stronger forces between molecules --> higher boiling point.
  • insoluble as they are non-polar molecules (means that they do not have positive or negative ends like water molecules do).
  • have strong C-C and C-H bonds meaning that they are very unreactive (except with oxygen). This is because a lot of energy is needed to break the bonds and also they are non-polar.
  • alkanes are saturated molecules because they have single bonds. Alkenes are unsaturated because they have double bonds and this also means that they are more reactive.
  • react with oxygen (combustion reaction) to make carbon dioxide and water.
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Alcohols

General facts about Alcohols

  • have an -OH functional group and their names end in '-ol'.
  • the alcohol formula is: CnH2n+1OH

Properties of Alcohols

  • weak acid as it does not fully dissociate. Reacts with metals and metal oxides/hydroxides just like HCl or any other strong acid would. Does not react with metal carbonates. Reacts with sodium to make salt and hydrogen gas.
  • very flammable.
  • soluble in water as they are polar molecules (have positive and negative ends like water molecules).
  • strong inter-molecular bonds --> higher melting and boiling points.

They can be used as solvents, fuels and even as a starting point for the manufacturing of other organic chemicals.

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Carboxylic acids

General facts about Carboxylic acids

  • have a -COOH functional group and their names end in '-anoic acid'.

Properties of Carboxylic acids

  • oraganic weak acids as they do not fully dissociate. They react like any other acids would making the same sort of products.
  • they are stronger than alcohols. They can react will metals (products = salt + hydrogen), metal oxides/hydroxides (products = salt + water) and metal carbonates (products = salt + carbon dioxide + water).
  • insoluble in water as they are not defined polaric molecules.

They have strong smells and tastes. e.g. sweaty socks stick because of carboxylic acids; rancid butter tastes disgusting because of carboxylic acids; and vinegar!

Wine and beer tastes like vinegar (dilute ethanoic acid) after it is left open in air because the ethanol in wine and beer oxidises to make ethanoic acid.

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Esters

General facts about Esters

  • have a -COO- functional group.
  • word equation for esterification reaction:

alcohol + carboxylic acid --> ester + water

Properties of Esters

  • they are slightly polar however insoluble in water.
  • they have a volatile property. Volatile means it evaporates easily.

Method of making Esters (explained in detail in the next card)

Refluxing --> Distillation --> Purification --> Drying

Fats and oils are esters made of glycerol and fatty acids. These can be saturated or unsaturated.

* arrow for this reaction should be the arrow going both ways indicating that the reaction is reversible + the reaction needs a catalyst (usually concentrated H2SO4.

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Making Esters in detail

Making and Ester

1. Refluxing: the alcohol and ester are heated with a little concentrated H2SO4 in a flask with a condenser attached. The condenser prevents evaporation of the mixture.

2. Distillation: here the mixture is heated and the product collected at its boiling point. This separates the product from most of the impurities.

3. Purification: product is shaken with reagent in a separating funnel. Impurities dissolve in reagent (which can then be run off).

4. Drying: solid drying agent is added to product. The drying agent absorbs the water from the product. Filter the product to remove the solid drying agent from the product.

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Comments

FutureMedic

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94Y86

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Namita

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Simi

Why Nami, who knew I could stalk you across this site :3 Hiya

Namita

no way!! SIMI!! xD you got in???? ha ha...about time i would say :P

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