Petroleum: An Energy Source

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Petroleum An Energy Source
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History of petroleum

• For almost 5000 years, humans have used petroleum
  in small amounts
• For the last 150 years (1st oil well 1859)
  society is much more dependent on oil

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Energy Tracing

• tracing the history of energy used in the
  production and creation of a material or object
• Imagine a paperclip
• What events in the productionall the way to
  getting it to schoolrequired the use of energy?
• Work in a group to brainstorm a list

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Paperclip
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Fossil Fuels

• Evidence indicates that fossil fuels originated
  from biomolecules of prehistoric plants and
  animals in ancient seas 500 million years ago

Paleozoic forest
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• These species died and eventually became covered
  with sediments
• Pressure, heat and microbes reduced living things
  to carbon deposits

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• Burning fossil fuels releases carbon that was
  originally captured by those plants (or plants
  eaten by animals) in photosynthesis
• Like buried sunshine!

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Energy

• Fossil fuel is chemical energy, energy stored in
  chemical bonds
• Chemical energy is a type of potential energy
• When fuel burns, bonds break and reactant atoms
  reorganize to form new bonds
• Products have less potential energy (chemical
  energy) than reactants
• Some of the original stored energy was released
  in the form of heat and light

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Example Burning Methane

• CH4 2 O2 ? CO2 2 H2O Energy
• Reaction takes place in two steps
• Bond breaking
• Bond making

Uses energy to break bonds endothermic
Releases energy to make bonds exothermic
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Bond breaking

• Energy CH4 CO2 ? C 4 H 4 O

Bond making
C 4 H 4 O ? CO2 2 H2O Energy
C 4 H 4 O
high
Chemical potential energy
CH4 CO2
CO2 2 H2O
low
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Endothermic or Exothermic?

• Depends on whether overall more energy is
  released or used
• If the forward reaction is exothermic, the
  reverse is endothermicso you can reverse a
  reaction and reverse whether it is endo or
  exothermic
• Example burning H gas (creating water) releases
  energy so, breaking bonds of water ________ energy

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Remember

• Despite all these conversions in energy,
• ENERGY CANNOT BE CREATED OR DESTROYED
• This is called.

Law of Conservation of Energy