Formation of Calcium Carbonate

1
Formation of Calcium Carbonate

• Investigation 5 Limestone
• Earth History
• Grade 6

2
Quick Write

• In your ISN on page 74, titled Limestone Fizz
  Quick Write, please respond to the following
  question
• How do you think limestone forms? What process of
  sedimentation might produce a rock that fizzes
  with dilute acid?

3
Fizzing of Limestone

• Limestone fizzes in acid because they contain
  calcite.
• Calcite is one form of calcium carbonate.
• The fizzing is CO2 (Carbon Dioxide) being
  releases.

4
Think About This

• Scientists want to know
• Where does calcium carbonate come from, and how
  does it get into the limestone?

5
Formation of Limestone

• Calcium carbonate does not dissolve in water
  (H2O).
• If calcium carbonate forms in the sea or falls
  into the sea, it will sink to the bottom forming
  a layer.
• The layer turns to rock and the rock is
  limestone.

6
Where Does Calcium Carbonate Come From?

• Calcium Carbonate forms in the sea in two main
  ways

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Where Does Calcium Carbonate Come From?

• Type1
• Some animals use calcium to make their bones,
  shells, and scales.
• The calcium in shells combines with carbon and
  oxygen to make CaCO3 (calcium carbonate).
• When the animal dies, the calcium settles to the
  bottom and can be incorporated into the forming
  rock.
• Example Oyster shells can be a main component of
  limestone.

8
Where Does Calcium Carbonate Come From?

• Type 2
• Calcium carbonate also forms when CO2 (carbon
  dioxide), exhaled by organisms living in the sea,
  reacts with calcium in the water.
• Calcium carbonate forms right in the water and
  precipitates to the bottom.
• Example the reside at the bottom of our cups.

9
Calcium Carbonate Chemical Equation

• Ca(OH)2 CO2 CaCO3 H20