OCR Chemistry Salters F331

Created by: Michael Herron
Created on: 15-12-12 09:55

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F331
- Fuels
  - Octane Number
    - Tendency to auto-ignite
      - High octane No. decreases the tendency
  - Emissions
    - Hydrogen -> harmless water
      - Hydrogen from electrolysis of NaCl(aq)
        Hydrocarbons -> CO2, CO, Sulphur & Nitrogen compounds
        Carbon particles from incomplete combustion
    - Hydrocarbons -> CO2, CO, Sulphur & Nitrogen compounds
      - Carbon particles from incomplete combustion
  - Functional groups
    - Alcohol: C-OH
    - Halogenoalkane: C-Halogen
    - Aldehyde: CH=O
    - Alkene: C=C
    - Ketone: RCR=O
    - Alkane: C-H
    - Carboxylic acid: COH=O
    - Ether: COC
- Energy levels
  - Shielding
    - e's closer to a nucleus more attracted
    - More energy levels cause e's to be further from the nucleus
  - Spectra
    - Absorption
      - Black lines, coloured background.
    - Emission
      - Coloured lines, dark background
        e's gain energy & are excited
        They move to higher E levels
        Drop back emitting a photon
        E levels are specific
        Lines of specific frequency formed
- Enthalpy
  - Longer chains, greater enthalpy, as more bonds broken, same No. formed of the same type.
    - Fuels
      - Octane Number
        Tendency to auto-ignite
        High octane No. decreases the tendency
      - Emissions
        Hydrogen -> harmless water
        Hydrogen from electrolysis of NaCl(aq)
      - Functional groups
        Alcohol: C-OH
        
        Halogenoalkane: C-Halogen
        
        Aldehyde: CH=O
        
        Alkene: C=C
        
        Ketone: RCR=O
        
        Alkane: C-H
        
        Carboxylic acid: COH=O
        
        Ether: COC
  - Hess's Law
    - Enthalpy change is the same, regardless of the route taken, provided the conditions stay the same.
    - To find the enthalpy change
      - E to break all bonds in reactants = DH + E to make all bonds in products
  - Catalysis
    - Heterogeneous
      - Different state to reactants
      - Reactants are adsorbed onto the surface
        Bonds in reactants weaken and break.
        New bond for in the products
        Products diffuse away
      - Zeolites
        Porous to increase SA
    - Homogeneous
      - Same state as reactants
    - Provide an alternate route with a lower activation energy
  - Enthalpy change with water = mcDT
    - -ve's: Heat loss to surroundings, not standard conditions, incomplete combustion, evaporation from wick
  - Entropy: the measure of disorder of a system, gases having the greatest entropy
- Shapes & Formula
  - Isomers: same atoms, different shape
  - Structural formula: letters & bonds
  - Skeletal formula: just bonds
  - Bond angles
    - 2 areas of e density: 180
    - 3 areas of e density: 120
    - 4 areas of e density: 109
    - 6 areas of e density: 90
    - Areas of electron density repel to move as far away as possible from each other
  - Empirical formula: simplest ratio of atoms
  - Molecular formula: just letters
  - Systematic name
    - Longest chain on alkane
      - Any functional groups added as prefix
        If more than one possible isomer, numbering always starts from the end that would give the functional groups the smallest possible number
        If there is more than one functional gorup, they are placed in alphabetical order

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OCR Chemistry Salters F331

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