Chemistry

• Catenation


  Carbon atoms' ability to bond to themselves in long chains

  
• Tetravalency


  Carbon's valency is 4 and it forms strong bonds with itself

  
• Carbon atoms


  • Can form straight chains
  • Can form branched chains
  • Can form rings

  
• Hybridisation


  The combination of the usage of the ONE s electron and the THREE "p" electrons in bond formation
• Homologous series


  Groups of organic compounds with the same general formula, same functional group, similar chemical properties, graduating physical properties as the number of carbon atoms increases, and the masses of consecutive members differ by 14 g or by a -CH2 group

  
• Empirical formula


  The simplest whole number ratio of atoms in a compound
• Molecular formula


  The actual number of atoms in a compound
• Structural/displayed formula


  The diagrammatic representation of an organic molecule showing the arrangement of atoms
• Condensed formula


  The groups of atoms arranged around each carbon atom in the compound, without showing the arrangement of the atoms

  
• Skeletal formula


  The bare structure of the compound where carbon and single hydrogen atoms are not shown, represented by a series of straight lines and bends

  
• Structural isomerism


  • Occurs when 2 or more compounds have the same molecular formulae but their atoms are arranged differently
  • Categories: chain, functional, positional

  
• Stereoisomerism


  • Occurs when 2 or more compounds have the same molecular and structural formulae but the atoms are arranged differently in space
  • Categories: geometric/cis-trans isomerism, optical isomerism

  
• Chiral carbon atom


  A carbon atom with four different atoms or groups of atoms attached to it, resulting in no line of symmetry

  
• Enantiomers


  Mirror images of compounds with chiral carbon atoms that are non-superimposable

  
• Inductive effect


  Atoms or groups of atoms with electronegative atoms are electron withdrawing and have a negative inductive effect (-I)
• Mesomeric effect


  The same as the inductive effect but it occurs in multiple bonds
• Homolytic fission


  Breakage of a covalent bond with atoms of similar or same electronegativity resulting in the formation of free radicals
• Heterolytic fission


  Breakage of a covalent bond with atoms of different electronegativities with the formation of a cation and an anion
• Electrophile


  An electron loving species attracted to negatively charged centres
• Nucleophile


  A nucleus loving species attracted to positively charged centres
• Hydrolysis


  The splitting of a molecule using water or the reaction of a molecule with water
• Structural isomers with molecular formula C4H10


  • 2-methylpropane
  • Butane

  
• Positional isomers


  • 1,2-dichlorobenzene
  • 1,3-dichlorobenzene

  
• Functional isomers


  • Ethyl Alcohol
  • Dimethyl Ether
• Geometric isomers


  • trans-1,2-dichloroethene
  • cis-1,2-dichloroethene

  
• Enantiomers are identical in every way in terms of chemical and physical properties except that one rotates plane polarised light to the left and the other rotates plane polarised light to the right by the same degree
• If there are equal concentrations of both enantiomers in a mixture, there would be no observed optical activity and the mixture would called a racemic mixture or a racematate
• Carbon chain length


  Decreases with length of carbon chain
• Carbonyl group


  Can act as a base

  
• Carbonyl group (C=O)


  • Polar
  • Can form hydrogen bonds with water

  
• Carboxylic acids


  • Low volatility
  • Higher boiling points due to hydrogen bonding

  
• Carboxylic acids


  Methanoic acid is stronger than ethanoic acid

  
• Carboxylic acids


  • Acetic acid (vinegar)
• Esters


  • Polar, but no hydrogen bonds
  • More volatile than carboxylic acids, lower boiling points
  • Liquids at room temp for smaller molecules
  • Solubility decreases with size of chain for small esters

  
• Amides


  • Polar, amine can hydrogen bond
  • High melting point due to hydrogen bonding
  • Amides are liquids or solids at room temp
  • Amine part of amide is basic

  
• Amides


  • Proteins (polypeptides)
  • Nylon
• All organic compounds ultimately come from crude oil
• Crude oil is a mixture of organic compounds
• Fractional distillation of crude oil

  Obtain various fractions containing alkanes and alkenes
• Fractions obtained from crude oil distillation


  • Gasoline
  • Diesel
  • Other fractions