CHAPTER 13 Carbonates Notes IGCSE Cambridge

This Chapter Studies Carbonates , These are compounds which contain the carbonate anion in its composition . Let's see how can we write the carbonate ion and some of its famous compounds 

The Calcium Carbonate is a main component of limestone , quarried in millions of tons each day all over the world , and very important in many industries and uses . So we will study it extensively and some of its related compounds as lime and slaked lime.

The Limestone Cycle

Detection of the Carbon dioxide gas (test for CO2 gas)

Uses of Lime , Slaked lime and limestone

What is required from you in this Chapter ?

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1 - Understand the different compounds containing calcium like 

• Calcium Oxide CaO (lime) also called unslaked lime or quicklime

• Calcium Carbonate CaCO₃ (main component of limestone)

• Calcium Hydroxide Ca(OH)₂; called slaked lime  or hydrated lime

• Lime water or Calcium Hydroxide dissolved in water

2 understand how can you change from one compound to another ?

3- Understand This last step (process no 4 ) which is useful in a side reaction , we can use it to identify the presence of CO2 gas anytime  by detecting the milky color of calcium carbonate formed

i.e the solution color changes from colorless (calcium hydroxide solution  or  lime water ) to milky ( limestone formed: calcium carbonate ) 

4 - Note that the first step (process no 1 ) is known as Thermal decomposition , as we have studied in the First Chapter raising the temperature of a solid causes its melting into a liquid form , but in some substances before melting , another process might happen  which is the breaking down of the substance into more simple compounds 

In our example here the calcium carbonate (limestone) here is broken down into Calcium oxide ( lime) and carbon dioxide gas produced

since heat is used we call this decomposition ➡️ Thermal decomposition  

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5- Understand some uses of lime and slaked lime

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