basic oranic

• Hydrolysis


  Reaction with water/aqueous hydroxide ions that breaks down a chemical compound
• Hydrolysis


  1. Requires a source of heat

  2. Carried out under reflux

  3. Substitution reaction

  4. Products are an alcohol and a halide (and an H+ ion if the reaction was done with water)
• Hydrolysis equations


  • Aqueous hydroxide ions used
  • Water used
• Aqueous hydroxide ions source

  Aqueous sodium hydroxide
• Nucleophilic substitution mechanism


  1. Halide atoms are more electronegative than hydrogen or carbon

  2. Bond between halide and carbon is polar

  3. Halide atom is delta negative, carbon atom is delta positive

  4. Hydroxide ion has lone pair, attracted to electron deficient carbon

  5. Lone pair repels shared electrons between carbon and halogen

  6. Bond breaks via heterolytic fission
• Nucleophile


  Electron pair donor
• Relative rates of hydrolysis of halogenoalkanes


  1. Measure out equal volumes of 3 halogenoalkanes

  2. Add ethanol

  3. Add silver nitrate solution

  4. Place in water bath at 50 degrees celsius for 5 minutes

  5. Mix contents and time how long for silver halide precipitate to form

  6. Rate = 1/time
• When comparing reaction rates, ensure halogenoalkanes have same chain length
• Silver nitrate is used as the silver ions react with the halide ions to form an insoluble precipitate, showing the reaction has occurred
• Iodobutane is fastest in reacting, followed by bromobutane, then chlorobutane
• Reason for relative rates

  • As you go down group 7, electronegativity decreases
  • Greater electronegativity means greater bond enthalpy
  • Lower bond enthalpy means bond is easier to break, leading to faster reaction
  • Bond enthalpy has greater part in determining rate than bond polarity
• Ozone


  • Formula is O3
  • Absorbs UVb so only 5% reaches earth
  • Absorbs UVc fully
  • UVa reaches earth as it has longer wavelength
• Ozone formation


  1. Oxygen molecules exposed to UV

  2. UV splits oxygen molecule (homolytic fission)

  3. Oxygen atom reacts with oxygen molecule to form ozone

  4. Ozone absorbs UV and breaks back down into oxygen
• Ozone formation and breakdown have become equal over millions of years, reaching equilibrium
• Ozone depletion


  • Caused by chemicals like CFCs introduced by humans
  • CFCs split via homolytic fission to form chlorine radicals
  • Chlorine radicals catalytically destroy ozone in propagation reactions
  • 1 chlorine radical can destroy 100,000 ozone molecules
• Helping ozone recover


  1. Measure and monitor ozone and ozone-depleting chemicals

  2. Provide data to governments to make policies and protocols

  3. Develop alternatives to CFCs like CO2 and HFCs

  4. However, replacements can be greenhouse gases
• Nitrogen oxides are also bad for ozone
• Greenhouse effect


  • Without it, global temperature would be -20 degrees
  • Greenhouse gases like CO2, water vapour, methane absorb and re-emit infrared, warming the atmosphere
  • Levels of these gases have increased due to human activities, enhancing the greenhouse effect
• Global warming potential


  • Measure of how much a gas can contribute to global warming
  • Depends on concentration and ability to absorb infrared
  • CO2 has a global warming potential of 1, nitrogen oxides have 160
• Effects of increased greenhouse effect

  • Rising sea levels
  • Adverse weather
  • Global warming
• Combating greenhouse effect


  1. Monitor gas levels and sea levels

  2. Develop alternative energy sources

  3. Develop more efficient combustion engines

  4. Carbon capture and storage (pressurised underground, mineral storage, decarbonised fuels)
• Homologous series studied at AS

  • Alkanes
  • Alkenes
  • Alcohols
  • Carboxylic acids
  • Aldehydes
  • Ketones
  • Halogenoalkanes
  • Esters
• Alkanes


  Don't have a functional group, made up of carbon-carbon single bonds and hydrogen (has the general formula CnH2n+2)
• Alkenes


  The functional group is the double carbon carbon bond
• Alcohols


  The functional group is the -OH (hydroxyl) group bound to a saturated carbon atom (the general formula for an alcohol is CnH2n+1 OH)
• Carboxylic acids


  The functional group is the (carboxyl) group (the general formula for a carboxylic acid is CnH2n+1 COOH)
• Aldehydes


  The functional group is
• Ketones


  The functional group is part of the carbon chain, rather than at the end like in aldehydes
• Halogenoalkanes


  The functional group is a halogen replacing one of the hydrogens
• Esters


  Their functional group is
• The area that is to the right of the functional group makes up the first part of the name, and the area to the left of the functional group makes up the second part of the name
• Alkanes


  Radical substitution mechanism
• The reactions of halogens with alkanes are substitution reactions
• Addition reactions are when two reactants make one product, whereas substitution is where two reactants make two products (one of which is a haloalkane)
• In these reactions one of the hydrogens in the alkane is swapped with one of the halogen atoms, and the swapped hydrogen atom then bonds with the other halogen atom to form a compound
• These radical substitution reactions require UV in order to occur (a form of radiation/energy)
• Radical substitution mechanism of alkanes

  1. Initiation

  2. Propagation

  3. Termination
• Initiation


  The halogen molecule undergoes homolytic fission (the diatomic molecule's bond is split evenly down the middle, giving each halide ion one electron from the bond)
• Mass spectrometry


  Technique used to analyse organic compounds
• Mass spectrometry of organic compounds

  • Able to tell the Mr of the molecule
  • Able to tell what the molecule is made up of