alkanes

• What is crude oil primarily composed of?


  A mixture of different hydrocarbons
• How does fractional distillation separate crude oil?


  By utilizing different boiling points of hydrocarbons

  
• What are the steps involved in the fractional distillation of crude oil?


  1. The mixture is vaporized and fed into the fractionating column.
  2. Vapors rise, cool, and condense.
  3. Products are siphoned off for different uses.
• Where are products with short carbon chains collected in the fractionating column?


  At the top of the column
• Why do products with long carbon chains condense at the bottom of the fractionating column?

  Because they have higher boiling points
• What happens to the compounds collected from the fractionating column?

  They are broken down further via cracking
• What is the purpose of cracking in the context of hydrocarbons?


  To break down longer carbon chains into smaller, more useful molecules
• What are the two main types of cracking and their characteristics?

  • Thermal Cracking:
  • Produces alkanes and alkenes
  • High temperatures (~1200 K) and high pressures (~7000 kPa)

  
  

  • Catalytic Cracking:
  • Produces aromatic compounds
  • Lower temperatures (~720 K) and normal pressure with a zeolite catalyst
• Why are alkanes considered good fuels?

  They release a lot of energy when burned
• What products are formed during the complete combustion of alkanes?

  Carbon dioxide and water
• What occurs during incomplete combustion of alkanes?


  Carbon monoxide is produced alongside water
• What is a toxic byproduct of alkane combustion?

  Carbon monoxide
• What is the function of a catalytic converter?


  To convert harmful products into more stable products
• What catalyst is used in catalytic converters?


  Rhodium
• What are carbon particulates and why are they a concern?


  Small fragments of unburned hydrocarbons that can cause respiratory problems
• What is flue gas desulfurization used for?


  To remove sulfur impurities from waste products
• What can sulfur impurities lead to in the atmosphere?


  Acidification of water
• What are the environmental impacts of pollutants from alkane combustion?


  • Contribute to global warming
  • Cause acid rain
  • Lead to health issues in humans
• How do alkanes react with halogens?


  In the presence of UV light to produce halogenoalkanes
• What are the steps in the chlorination of alkanes?


  1. Initiation - halogen bonds are broken.
  2. Propagation - hydrogen is replaced and Cl• radical is reformed.
  3. Termination - two radicals join to form a stable product.
• What is a free radical in the context of chlorination of alkanes?


  A reactive intermediate produced during the reaction
• How can the conditions of the chlorination reaction be altered?


  To favor the termination step and limit substitutions