organic chemistry

• What are hydrocarbons defined as?

  Compounds formed from carbon and hydrogen only
• What is the name of the hydrocarbon with the formula C4H10?

  Butane
• What is the molecular formula for methane?

  C1H4
• What is the molecular formula for ethane?

  C2H6
• What is the molecular formula for propane?

  C3H8
• What is the general formula for alkanes?

  CnH2n+2
• If an alkane has three carbon atoms, what is its molecular formula?

  C3H8
• What is the molecular formula for octane, which has eight carbon atoms?

  C8H18
• What happens to the molecular structure of propane if one of its single bonds is changed to a double bond?

  It would no longer be classified as an alkane
• What are the first four alkanes in the series?

  1. Methane (C1H4)
  2. Ethane (C2H6)
  3. Propane (C3H8)
  4. Butane (C4H10)
• What is a homologous series in organic chemistry?

  • A group of organic compounds with similar properties
  • React in a similar way
  • Have a general formula
• What is the characteristic of alkanes regarding double bonds?

  They contain no double bonds
• What are the trends in the properties of alkanes as the carbon chain length increases?

  • Boiling point increases with chain length
  • Shorter alkanes are gases at room temperature
  • Longer alkanes are liquids or solids at room temperature
  • Shorter alkanes are more volatile
  • Longer alkanes are more viscous
  • Shorter alkanes are more flammable
• Why do shorter alkanes have lower boiling points?

  Because they have shorter carbon chains
• What does it mean for an alkane to be more volatile?

  It evaporates more easily
• How does viscosity relate to the length of the carbon chain in alkanes?

  Longer alkanes are more viscous
• What is one of the main uses of hydrocarbons like alkanes?

  As fuel
• What is crude oil primarily composed of?

  A mixture of different hydrocarbons
• What process is used to separate hydrocarbons in crude oil?

  Fractional distillation
• Why are shorter hydrocarbons considered better fuels?

  They are more flammable
• What is the main purpose of cracking in hydrocarbons?

  To break down longer hydrocarbons into shorter, more flammable ones
• What is produced when long chain alkanes are cracked?

  A shorter alkane and an alkene
• What is the significance of alkenes in relation to alkanes?

  Alkenes are unsaturated and more reactive than alkanes
• What happens when bromine water is added to alkenes?

  It decolorizes from orange to colorless
• What is crude oil primarily composed of?

  A mixture of different hydrocarbons
• What process is used to separate hydrocarbons in crude oil?

  Fractional distillation
• Why are shorter hydrocarbons considered better fuels?

  They are more flammable
• What happens to longer chain hydrocarbons during cracking?

  They are broken down into shorter, more flammable hydrocarbons
• What type of reaction is cracking?

  A thermal decomposition reaction
• What are the two methods of cracking mentioned?

  Catalytic cracking and steam cracking
• What is the first step in both catalytic and steam cracking?

  Heat and vaporize the long chain hydrocarbons
• What is used as a catalyst in catalytic cracking?

  Hot powdered aluminium oxide
• What happens to long hydrocarbons in catalytic cracking when they contact the catalyst?

  They split apart into two smaller hydrocarbons
• In steam cracking, what is mixed with the vaporized hydrocarbons?

  Steam
• What is the result of heating vaporized hydrocarbons in steam cracking?

  Long hydrocarbon chains split apart into shorter ones
• What is the general equation for the cracking of long chain alkanes?

  Long chain alkane → Shorter alkane + Alkene
• What is the structural difference between alkenes and alkanes?

  Alkenes have a double bond, while alkanes have only single bonds
• What does it mean for alkenes to be unsaturated?

  They contain at least one double bond
• Why are alkenes more reactive than alkanes?

  Because they have a double bond
• What is the test for alkenes?

  Adding bromine water