Lesson 27 Thermal decomposition of limestone marble

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Lesson 27 Thermal decomposition of limestone /
marble

• What precautions have to be taken in thermal
  decomposition of limestone ?
• How is the presence of calcium ion in
  limestone/marble be identified ?
• How is the presence of carbonate ion in
  limestone/marble be identified ?
• What is limewater ? How is it prepared ?
• Why does limewater turn milky in the presence of
  carbon dioxide ?

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What precautions have to be taken in thermal
decomposition of limestone ?
Calcium carbonate (limestone)
calcium oxide (quick lime)
carbon dioxide

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What precautions have to be taken in thermal
decomposition of limestone ?

• The delivery tube has to be removed from the
  limewater before the removal of bunsen burner.
• Otherwise, the air pressure will forces the
  limewater into the hot boiling tube and sucking
  back will occur.
• The cold limewater will crack the hot boiling
  tube.

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How is the presence of calcium ion in
limestone/marble be identified ?

• The presence of calcium ion particle can be
  identified by flame test in which a brick red
  flame will be observed.

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How is the presence of carbonate ion in
limestone/marble be identified ?

• The presence of carbonate ion is usually tested
  indirectly by the action of acid to give carbon
  dioxide get which turns limewater milky.

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What is limewater ? How is it prepared ?

• Limewater is solution of calcium hydroxide
  (usually saturated).
• It is prepared by dissolving of solid calcium
  hydroxide (slaked lime) formed from the action of
  water on calcium oxide (quicklime)

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Why does limewater turn milky in the presence of
carbon dioxide ?

• Soluble calcium hydroxide in limewater reacts
  with carbon dioxide to form white precipitate of
  calcium carbonate which gives the mixture a milky
  appearance.

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Classwork(Do them on your textbook)

• pg98 Q5.1,
• pg103 Q10,11,12,16
• pg104 Q24