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Course: Science — Third Preparatory
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Science — Third Preparatory

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Unit 1 — Chemical Reactions and Their Environmental Impacts

Science — Third Preparatory

Unit 1 — Chemical Reactions and Their Environmental Impacts

2.7 Detecting the products of combustion

2.7 Detecting the products of combustion

  • Activity. Burn natural gas (hydrocarbon) in a Bunsen burner and pass the products through an apparatus: first a U-tube surrounded by ice that contains light blue anhydrous cobalt chloride paper, then through clear limewater.
  • Observations:
  • The ice cools the gases so the water vapour condenses; the blue cobalt chloride paper turns pink, showing that water is formed.
  • Limewater turns milky , showing that carbon dioxide is formed.
  • So the complete combustion of a hydrocarbon forms water and carbon dioxide, as the equation says.
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