crude oil and alkenes

• What is crude oil primarily composed of?

  A mixture of 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 hydrocarbons
• What type of reaction is cracking?

  Thermal decomposition reaction
• What does thermal decomposition mean?

  Breaking down molecules by heating
• What are the two methods of cracking?

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

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

  Hot powdered aluminium oxide
• What is mixed with hydrocarbons in steam cracking?

  Steam
• What is produced when long hydrocarbons are cracked?

  Shorter hydrocarbons and alkenes
• What is the balanced equation for cracking decane?

  Decane → Octane + Ethene
• How do you determine the formula of the unknown alkane in cracking?

  Subtract carbons and hydrogens of products from reactants
• What is the formula of the unknown alkane when decane is cracked into ethene?

  C₈H₁₈
• What is a homologous series?

  A group of similar compounds with similar properties
• What distinguishes alkenes from alkanes?

  Alkenes have a double bond; alkanes have single bonds
• Why are alkenes more reactive than alkanes?

  Due to the presence of a double bond
• What happens when bromine water is added to alkenes?

  It decolorizes from orange to colorless
• What can alkenes be used to produce?

  Polymers and other chemicals
• What are the key features of alkenes compared to alkanes?

  • Alkenes have a double bond; alkanes have single bonds
  • Alkenes are unsaturated; alkanes are saturated
  • Alkenes are more reactive than alkanes
• What are the steps involved in the cracking process?

  1. Heat long chain hydrocarbons
  2. Vaporize them
  3. For catalytic cracking, pass vapor over catalyst
  4. For steam cracking, mix vapor with steam and heat
  5. Split long hydrocarbons into shorter ones
• How do you write a balanced equation for cracking?

  1. Identify reactants and products
  2. Count carbons and hydrogens
  3. Ensure the same number on both sides
  4. Adjust products as necessary
• What process is used to separate crude oil into components?

  Fractional distillation
• What type of fuel is crude oil classified as?

  Fossil fuel
• What are the main components of crude oil?

  Mostly hydrocarbons
• What are the most common hydrocarbons found in crude oil?

  Alkanes
• How is crude oil formed?

  From remains of dead plants and animals
• What type of organisms primarily contribute to crude oil formation?

  Plankton
• What conditions are necessary for the formation of crude oil?

  High pressures and temperatures
• How long does it take for crude oil to form?

  Millions of years
• Why is crude oil considered a finite resource?

  It takes a long time to form
• What term is used for fuels like coal, oil, and gas?

  Non-renewable fuels
• What is the first step in fractional distillation of crude oil?

  Feed the oil into a chamber and heat it
• What happens to the gaseous mixture in the fractionating column?

  It cools and condenses into liquids
• How do boiling points affect the separation of hydrocarbons?

  Higher boiling points condense first
• What is an example of a product obtained from the bottom of the fractionating column?

  Bitumen
• What are the uses of heavy fuel oil?

  Heating oil and lubricating oil
• What fuels are produced from shorter chain hydrocarbons?

  Diesel and petrol
• What is LPG primarily composed of?

  Propane and butane
• How do the flammability characteristics of hydrocarbons vary?

  Shorter chains are more flammable