Combination & Decomposition Reactions
There are four different types of chemical reactions:
- Combination or Synthesis Reactions
- Decomposition Reactions
- Single Replacement Reactions
- Double Replacement Reactions
In this session, We will focus on Combination and Decomposition chemical reactions.
Previous learning sessions:
Combination or Synthesis Reactions
Combination word means combine or joining of two or more things to each other. Something similar happens with the Combination or Synthesis reactions.
A reaction in which more than one (or many) reactants take apart and get combined together to form one product. Like two or more elements or compounds which get combined and form one another compound.
So, this reaction have multiple reactants but form only one product. Such kind of reaction is considered as Combination or Synthesis reaction.
Examples:- Formation of Salt
- Sodium + Chlorine → Sodium Chloride
- 2Na + Cl2 → 2NaCl
- Burning of Coal
- Carbon + Oxygen → Carbon Dioxide
- C + O2 → CO2
- Burning of the Rocket Fuel (Liquid Hydrogen)
- Hydrogen + Oxygen → Water
- 2H2 + O2 → 2H2O
Decomposition Reactions
Decomposition word means breaking or splitting of one complex substance into two or more smaller substances. Something similar happens with the Decomposition reactions. It is opposite of Combination reaction.
A reaction in which one reactant element or compound broken down to form multiple (two or more) products.
It means one reactant which take apart in reaction and it get form two or more products. This kind of reaction is considered as Decomposition reaction.
To break any complex substance (compound) we need energy either in form of light or heat or electricity or any other kind of energy.- Energy is required for decomposition reaction to occur.
- Energy in the form of Heat, Light or Electricity.
1. Thermal Decomposition Reaction – Reactions which require heat energy to break complex compound
2. Electrolysis Decomposition Reaction – Reactions which require electric energy to break complex compound
When a complex compound breaks, it also release energy.
Decomposition reactions are also classified into another two types based on reaction net result of energy.1. Endothermic Decomposition Reaction
a. If the net amount of energy required is more than energy released, then it is called Endothermic Decomposition reaction
b. Energy required is greater than energy released
2. Exothermic Decomposition Reaction
a. If the net amount of energy required is less than energy released, then it is called Exothermic Decomposition reaction
b. Energy required is less than energy released
