Self Ignitions and runaway chemical reactions

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Self Ignitions and runaway chemical reactions
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Production of pyrophoric iron

• Apparatus
• Safety
• Chemicals
• Method

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Apparatus

• Below is a list of the apparatus we used
  during the experiment
• - 3 test-tubes
• - 1 bunsen burner
• - 2 test-tube holders
• - 1 glass file
• - 4 tiles

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Safety

• In order to ensure our safety during the
  experiment and reduce hazards we had to do the
  following
• - wear a lab coat
• - wear safety goggles

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Chemicals

• Iron oxylate (Fe(CO2O4)

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Method (step 1)

• To do the experiment, we heated several
  test-tubes using the bunsen flame till a
  constriction was formed.

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Method (step 2)

• Once a constriction was formed, we added 3 cm
  of iron oxalate to the testube and heated while
  the test tube was shaken untill the iron oxalate
  broke down into iron and CO2 (black in colour).

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Method (Step 3)

• The melted test-tube is scored at the tip and
  is opened by snapping off the tip. Then in a dark
  room, the pyrophoric iron ignites when it comes
  into contact with the air.

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Conclusion

• When Iron Oxalate decomposes thermally, gaseous
  CO2
• and elementary Iron are formed which explains the
• gradual black colouring of the product. The iron
• decomposes into a more finely distributed form so
  that
• it oxidises immediately upon contact with air and
  forms
• a flame.
• The pyrophoric iron is an example of a
  self-igniting
• substance. This means that care must be taken to
  prevent
• exposure to air. It is also important to avoid
  contact with
• combustible substances like methanol, ethanol,
  methane and other
• hydrocarbon fuels.
• The high surface area of pyrophoric iron will
  increase the possibility of
• a spontaneous exothermic reaction and may lead
  to an
• explosion.