Crude oil and Fuels

• Crude oil formed:

  When marine microscopic organisms sink to the bottom and over millions of years and intense heat and pressure it is formed.
• What is the composition of raw crude oil?

  A thick black liquid of various compounds
• What is fractional distillation used for?

  To separate hydrocarbons based on boiling points
• What happens to hydrocarbons in a fractionating column?

  They cool down and condense at boiling points
• What distinguishes alkenes from alkanes?

  Alkenes contain double bonds between carbon atoms
• What are the uses of alkenes?

  • Fuels
  • Production of polymers
  • Manufacturing other materials
• What is the role of vaporization in fractional distillation?

  It turns crude oil into gas for separation
• What are alkanes?

  Saturated hydrocarbons

  No double bonds

  Covelant bonds
• As the length of chain increases

  Temp increases

  Volatility decreases

  Viscosity increases

  Flammability decreases
• Fractional distillation:

  Crude oil is heated to vapour

  Vapour rises up fractionating column

  Fractionating collum is hotter at bottom cooler at top

  The fractions condense at their boiling point

  They are collected

  Longer chain alkanes at bottom

  Shorter chains rise to top

  Shorter chains have lower boiling points
• Problems with incomplete combustion of Alkanes

  Occurs in poorly maintained boilers/heaters

  Carbon monoxide combines hemoglobin preventing oxygen transport

  Colorless and odorless

  soot (particulates) breathing problems
• Observations incomplete combustion occurred

  Soot - unburnt carbon atoms
• Cracking:

  Process breaking down long chain hydrocarbons into shorter more useful chains using heat (thermal decomposition)
• Why is cracking used?

  To break down Alkanes into Alkenes
• Catalyst for cracking:

  broken pot/ aluminum oxide
• What is formed when microscopic organisms decompose over millions of years?

  Crude oil
• What is the main use of crude oil?

  Transport, heating, and cooking
• What type of hydrocarbons are alkanes?

  Saturated hydrocarbons
• How does the molecular formula of alkanes change as size increases?

  It changes by $CH_2$
• What is the molecular formula for methane?

  $CH_4$
• What is the molecular formula for ethane?

  $C_2H_6$
• What is the molecular formula for propane?

  $C_3H_8$
• What is the molecular formula for butane?

  $C_4H_{10}$
• Why are alkanes considered hydrocarbons?

  They consist of hydrogen and carbon bonded
• How many bonds does a carbon atom always have?

  Four
• How many bonds does a hydrogen atom always have?

  One
• What is the general formula for alkanes?

  $C_nH_{2n+2}$
• What is the general formula for alkenes?

  $C_nH_{2n}$
• What is the structure of propene?

  $H_2C=$$CH-C_2H_5$
• What is the structure of butene?

  $H_2C=$$CH-CH_2-CH_3$
• What are the products of complete combustion of hydrocarbons?

  Carbon dioxide and water
• What is the equation for the complete combustion of methane?

  $CH_4 +$$2O_2 \rightarrow CO_2 +$$2H_2O$
• What is the equation for the complete combustion of propane?

  $C_3H_8 +$$5O_2 \rightarrow 3CO_2 +$$4H_2O$
• What are the problems associated with incomplete combustion of alkanes?

  Produces carbon monoxide and soot
• What is the equation for incomplete combustion of methane?

  $2CH_4 +$$3O_2 \rightarrow 2CO +$$4H_2O$
• What is the process of fractional distillation used for?

  To separate crude oil into fractions
• What are the steps in the fractional distillation of crude oil?

  1. Crude oil is heated to vaporize.
  2. Vapors rise in the fractionating column.
  3. Fractions condense at their boiling points.
  4. Collected fractions are separated.
  5. Longer chains condense at the bottom.
  6. Shorter chains rise to the top.
• What is the relationship between the length of hydrocarbons and their properties?

  Shorter hydrocarbons have lower boiling points
• What happens to the properties of hydrocarbons as chain length increases?

  Higher boiling points and viscosity
• Why is hexadecane a suitable alkane for lubricating oil?

  It has a thick viscosity for lubrication