DF- general

• Standard enthalpy of combustion

  The enthalpy change that occurs when one mole of substance is burnt completely with oxygen under standard conditions (298K and 1 atmosphere of pressure) and standard states
• Standard enthalpy change of formation


  Enthalpy change that occurs when 1 mole of a compound is formed from its elements under standard conditions and states
• Standard enthalpy change of neutralisation

  The enthalpy change that occurs when one mole of hydrogen ions react with one mole of hydroxide ions to form one mole of water under standard conditions
• Bond enthalpy

  Amount of energy required to break one mole of bonds to give separate atoms all in a gaseous state (endothermic)
• Bond making - Exothermic

  Bond breaking - Endothermic
• Alkanes:

  
  

  Methane- 1

  Ethane- 2

  propane- 3

  Butane- 4

  Pentane- 5

  Hexane- 6

  Heptane- 7

  Octane-8

  Nonane- 9

  Decane- 10
• Aromatic

  Compounds containing a benzene ring
• Arene

  Aromatic hydrocarbon homologous series
• Aliphatic

  Compounds without a benzene ring
• Heterogenous catalyst

  Catalyst and reactant are different physical sates
• Model of a heterogenous catalyst

  1. Reactants adsorb onto surface of catalyst
  2. Bonds within reactant molecules weaken and break
  3. New bonds within product formed
  4. Products desorb from surface of catalyst
• How catalysts work

  • Providing an alternate reaction pathway with a lower activation energy
• Catalyst poison

  • When molecules adsorb strongly to the surface of a catalyst and block the active sites of the surface
• Cracking apparatus

  
• What bonds a double bond consists of

  Sigma and pie bond
• Bromine colours:

  • Bromine liquid - red brown
  • Bromine water - orange
  • Saturated molecule- stays orange
• Electrophile

  A positive ion or molecule with partial positive charge that will be attracted to a negatively charged region and react by accepting a pair of electrons to form a covalent bond
• Trans molecule (E)


  Group across bond
• Cis (Z)

  Group on same side of bond
• Molar volume

  The volume occupied by one mole of any gas at a certain temperature and pressure
• Alkane bond angle = 109.5

  Alkene bond angle = 120
• Structural isomerism - Same molecular formula, atoms bonded in a different order
• Chain isomerism - Breaking and reforming a C-C chain
• Position isomerism - Moving position of functional group
• Functional group isomerism - Transforming one functional group into another
• Types of structural isomers

  Chain isomers

  Position isomers

  Functional Group isomers
• Hess's Law - The enthalpy change of a reaction is independent of the route taken
• Single bond consists of a...

  Sigma bond
• Double bond consists of ...

  Sigma and pie bond
• Triple bond consists of ...

  One sigma and two pie bonds
• Why do larger chain alkanes have a higher boiling point than shorter ones

  More surface contact

  More van der Waals forces