Organic Chemistry

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  • Created by: Chesca
  • Created on: 16-05-13 17:10

Organic Chemistry

Organic molecules contain carbon atoms

Methane = 1 carbon atom

Ethane = 2 carbon atoms

Propane = 3 carbon atoms

Single bond between carbon atoms = ALKANE

Double bond = ALKENE

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Alcohols

Have the functional group O-H

Functional group = 'family' of organic compounds

  • family with same functional group = homologous series

H-C-O-H = Methanol (CH3OH)

H-C-C-O-H = Ethanol (C2H5OH)

 

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Carboxylic Acids

Ethanoic acid = vinegar

Carboxylic acids contain COOH

 

 

Methanoic acid = CHCOOH

Ethanoic acid = C2H3COOH

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Esters

Esters contain -COO-

(Must go in the middle of the molecule)

Ethyl Ethanoate: CH3COOC2H5

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Properties and uses of alcohols

Ethanol is main alcohol in alcoholic drinks

  • made by fermenting sugars from plant material

Alcohols dissolve similar substances to water

  • can dissolve other organic compounds
  • useful as solvents (perfumes,aftershaves,mouthwashes)
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Combustion

Ethanol + Methanol, are used as fuels

shows that alcohols are flammable

Ethanol burns with a clear blue flame

Ethanol + oxygen - carbon dioxide + water

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Reaction with Sodium & Oxidation

When alcohol added to sodium...

  • sodium 'fizzes', giving off hydrogen gas
  • reaction NOT as vigorous as one with water

Oxidation:

  • Combustion can oxidise an alcohol
  • alochol oxidised to carboxylic acid when boiled with acidified potassium dichromate solution (oxidising agent)
  • Ethanol oxidised to ethanoic acid
  • same reaction if ethanol exposed to air
  • microbes produce ethanoic acid from ethanol.
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Carboxylic Acids + Esters

Carboxylic acids form acidic solutions when dissolved in water

Carboxylic acids weak?

  • Carboxylic acids are called 'weak acids'/ Hydrochloric acid is a 'strong acid'
  • pH of 0.1mol/dm3 of hydrochloric acid is 1.0
  • pH of 0.1 mol/dm3 of ethanoic acid is 2.9

Why if same concentration, is one more acidic?

  • in water all acids ionise (molecules split to form H+ ions)
  • All acidic solutions have H+ ions in common
  • 'Strong acids' ionise completely in solution
  • 'Weak acids' don't completely ionise
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Making Esters

Carboxylic acids + acids = esters

acid (sulfuric acid) acts as a catalyst

Esters form are volatile (easily evaporate), sweet/fruity smells :)

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Ethanol in drinks

Alcohol associated with high blood pressure + heart disease

  • damage to liver!

Alcoholics are addicted to ethanol

Ethanol used in methylated spirits as solvents

Drinking 'meths' = liver failure, blindness, death

  • other chemicals added, makes hard to distill off ethanol
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Ethanol and esters in biofuels

Ethanol - biofuel = fermenting sugar from crops

Biodiesel = plant oils - esters

  • oil broken down into long chain carboxylic acids
  • Reacted with methanol or ethanol with catalyst to make esters used as biodiesel
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