Cracking

• What is meant by cracking in chemistry?

  Breaking down long chain hydrocarbons
• What are the conditions for catalytic cracking?

  High temperature and a catalyst
• What is the general formula for alkanes?

  $C_nH_{2n+2}$
• Why are long chain hydrocarbons not good fuels?

  They are not very flammable
• What is produced when cracking a long chain alkane?

  Shorter chain hydrocarbons and alkenes
• What is an alkene?

  A hydrocarbon with a double bond
• How do alkenes differ from alkanes in terms of reactivity?

  Alkenes are more reactive than alkanes
• What test is used to identify alkenes?

  Using bromine water
• What happens to bromine water when it reacts with an alkene?

  It turns colorless
• What is the importance of stating that bromine water turns colorless?

  It is the correct observation
• How do you balance a chemical equation for cracking?

  Ensure carbon and hydrogen atoms are equal
• What must be true about the number of atoms in a balanced equation?

  They must be the same on both sides
• If a cracking equation has 25 carbon and 52 hydrogen atoms on the left, how many are on the right?

  Must equal 25 carbon and 52 hydrogen
• In a cracking reaction with 40 carbon and 82 hydrogen atoms on the left, how many are needed on the right?

  Must equal 40 carbon and 82 hydrogen
• What are the two methods of cracking hydrocarbons?

  • Catalytic cracking: uses high temperature and a catalyst
  • Steam cracking: uses high temperature and steam
• What are the uses of alkenes?

  • Used to make polymers
  • Serve as starting materials for other chemicals
• What is the structure of an alkane?

  • General formula: $C_nH_{2n+2}$
  • Contains only single covalent bonds
• Why is cracking necessary in the oil industry?

  • Converts long chain hydrocarbons into shorter, more useful fuels
  • Addresses high demand for short chain hydrocarbons