Question

What type of reactions are represented by the following equations?
1. $CaC{O_3} \to CaO + C{o_2}$
2. $CaO + {H_2}O \to Ca{(OH)_2}$
3. $2FeS{O_4} \to F{e_2}{O_3} + S{O_2} + S{O_3}$
4. $N{H_4}Cl \to N{H_3} + HCl$
5 . $2Ca + O \to 2CaO$

Answer 1

A decomposition reaction is known as a chemical reaction in which one reactant breaks down into two or more products. A reaction in which two or more reactants combine to form a single product is known as a combination reaction. Combination reaction is also known as a synthesis reaction.

Complete answer:
1. $CaC{O_3} \to CaO + C{o_2}$
This is a decomposition reaction. Calcium carbonate decomposes to form carbon dioxide and calcium oxide. Carbonate compounds decompose when heated.
2. $CaO + {H_2}O \to Ca{(OH)_2}$
This reaction is a combination reaction as calcium oxide and water combine to form a single product that is calcium hydroxide.
3. $2FeS{O_4} \to F{e_2}{O_3} + S{O_2} + S{O_3}$
This is a decomposition reaction because three products are formed from one reactant. Ferrous sulphate decomposes to ferric oxide, sulphur dioxide and sulphur trioxide.
4. $N{H_4}Cl \to N{H_3} + HCl$
This is a decomposition reaction because two products are formed from one reactant. In this reaction, ammonium chloride decomposes to ammonia and hydrogen chloride.
5. $2Ca + O \to 2CaO$
This reaction is a combination reaction. In this reaction, calcium and oxygen are combined to form calcium oxide.

Note:
The opposite of a decomposition reaction is known as a combination reaction. Such reactions involve the formation of a single product from two or more reactants. The reaction in which a compound is decomposed due to heating is known as a thermal decomposition reaction. Combination reactions involve the formation of new bonds and this process releases a large amount of energy in the form of heat.