Topic C7 - organic chemistry:

• What are hydrocarbons made of?

  Hydrogen and carbon atoms
• What defines alkanes in organic chemistry?

  They have only single C-C bonds
• What does it mean for alkanes to form a homologous series?

  They react similarly due to structural similarities
• How many covalent bonds does each carbon atom form?

  Four covalent bonds
• What is the chemical formula for methane?

  CH₄
• What is the chemical formula for ethane?

  C₂H₆
• What is the chemical formula for propane?

  C₃H₈
• What is the chemical formula for butane?

  C₄H₁₀
• What happens to the boiling points of longer hydrocarbon chains?

  They have higher boiling points
• How does the flammability of longer hydrocarbons compare to shorter ones?

  They have lower flammability
• What is the general formula for alkanes?

  C_nH_2n+2

  
• What type of reaction is combustion?

  Exothermic reaction
• What is complete combustion?

  Oxidation with plenty of oxygen
• What is the general equation for the complete combustion of hydrocarbons?

  Hydrocarbon + oxygen → CO₂ + H₂O + energy
• Why are hydrocarbons used as fuels?

  They release lots of energy when combusted
• What is a fuel?

  A substance that releases heat when burnt
• What is fractional distillation used for?

  To separate hydrocarbons by boiling points
• What is crude oil?

  A mixture of hydrocarbons from dead organisms
• How is crude oil heated in fractional distillation?

  It is heated in a column
• Where do longer hydrocarbons condense in fractional distillation?

  Lower in the column
• Where do shorter hydrocarbons condense in fractional distillation?

  Higher in the column
• What are some uses of hydrocarbons obtained from fractional distillation?

  Fuels, polymers, and solvents
• What type of reaction is cracking of crude oil?

  Thermal decomposition reaction
• What is produced from cracking long-chain alkanes?

  Shorter-chain alkanes and alkenes
• What is catalytic cracking?

  Uses a hot catalyst to break down hydrocarbons
• What is steam cracking?

  Mixes hydrocarbons with steam and heats them
• Why are alkenes more reactive than alkanes?

  Due to their double bond
• What are the properties of longer hydrocarbon chains?

  • Higher boiling points
  • Lower flammability
  • Higher viscosity
• What are the main processes involved in the processing of crude oil?

  1. Fractional distillation
  2. Cracking
• What are the main products of cracking hydrocarbons?

  • Shorter-chain alkanes
  • Alkenes