ch4

• Hydrocarbon


  Compound consisting of hydrogen and carbon only
• Molecular formula


  Formula which shows the actual number of each type of atom
• Unsaturated


  Contains a C=C double bond
• Saturated


  Contain single carbon-carbon bonds only
• General formula


  Algebraic formula for a homologous series e.g. CnH2n
• Empirical formula


  Shows the simplest whole number ratio of atoms of each element in the compound
• Displayed formula


  Shows all the covalent bonds present in a molecule
• Drawing organic compounds


  Add the hydrogen atoms so that each carbon has 4 bonds
• Shape around carbon atom in saturated hydrocarbons


  • Tetrahedral, bond angle 109.5o
• Skeletal formula


  Simplified organic formula, shown by removing hydrogen atoms from alkyl chains, leaving just a carbon skeleton and associated functional Groups
• Structural formula


  Minimal detail that shows the arrangement of atoms in a molecule

  
• Structural formula examples


  • butane: CH3CH2CH2CH3 or CH3(CH2)2CH3
  • 2-methylbutane
  • But-2-ene
  • Butan-1-ol
  • cyclohexane
  • cyclohexene
• Hazard


  Substance or procedure that can has the potential to do harm
• Risk


  Probability or chance that harm will result from the use of a hazardous substance or a procedure
• Hazards and risks


  • Typical hazards are toxic/flammable /harmful/ irritant /corrosive /oxidizing/ carcinogenic
  • Risks can be reduced by working on a smaller scale, taking precautions specific to the hazard, using an alternative method that involves less hazardous substances
• Homologous series


  Families of organic compounds with the same functional group and same general formula
• Properties of homologous series


  • Show a gradual change in physical properties (e.g. boiling point)
  • Each member differs by CH2 from the last
  • Have same chemical properties

  
• Functional group


  Atom or group of atoms which when present in different molecules causes them to have similar chemical properties
• Functional group examples


  • Alkane
  • Alkene
  • Alcohol
  • Halogenoalkane
  • Aldehyde
  • Ketone
  • Carboxylic acid
  • Ester
• Precedence of functional groups


  Carboxylic acids >aldehydes>ketones>alcohols>alkenes>halogenoalkanes
• Naming carbon chains


  • Count the longest carbon chain and name appropriately
  • Find any branched chains and count how many carbons they contain
  • Add the appropriate prefix for each branch chain
• Naming functional groups


  • Position of functional group on carbon chain is given by a number
  • If suffix starts with vowel, remove -e from stem alkane name
  • If suffix starts with consonant or multiple functional groups, do not remove -e from stem alkane name
• Aldehydes


  Name ends in -al, C=O bond on first carbon
• Ketones


  Name ends in -one
• Carboxylic acids


  Name ends in -oic acid, no number needed for acid group
• Carboxylic acid examples


  • Propanoic acid
  • Ethanedioic acid
• Homolytic fission


  Bond breaks with each atom getting one electron from the covalent bond, forming free radicals
• Heterolytic fission


  Bond breaks with one atom getting both electrons from the covalent bond, forming ions
• Structural isomers


  Compounds with the same molecular formula but different structures
• Types of structural isomers


  • Chain isomers
  • Position isomers
  • Functional group isomers
• Isomers


  Compounds with the same molecular formula but different structures
• Types of structural isomerism


  • Chain isomerism
  • Position isomerism
  • Functional group isomerism
• Structural isomers


  • pentane
  • 2,2-dimethylpropane
  • 2-methylbutane
• Position isomers


  Compounds with the same molecular formula but different structures due to different positions of the same functional group on the same carbon skeleton
• Position isomers


  • 1-bromopropane
  • 2-bromopropane
• Functional group isomers


  • ethanol: an alcohol
  • Methoxymethane: an ether
• Cyclic and unsaturated hydrocarbons


  • Cyclohexane- cyclo alkane
  • hexene- alkene
• Alkenes and cyclo alkanes have the same general formula. Hexene and cyclohexane have the same molecular formula but have a different functional group
• EDEXCEL does not split structural isomers into the different categories. They are all classed as structural isomers
• Alkanes


  Saturated hydrocarbons