We have discussed different types of chemical reactions like – combination reactions, decomposition reactions, displacement reactions, and double displacement reactions.
Today we will find the answer to what is an endothermic reaction?
Endothermic reaction
Define Endothermic reaction
The chemical reaction in which heat
energy is supplied from outside, to complete the reaction, is called an
endothermic reaction.
A+B + heat →C+D
In endothermic reactions, the total amount of
energy of reactants is lesser than the total energy of products.
Energy of reactants < energy of
products
i).`N_2 + O_2 + 180.5kJ →2NO`
ii).`H_2 + 435.6kJ → 2H`
Why heat is absorbed in an endothermic reaction?
The energy needed to break the bonds
in the reactants is greater than the energy released when new bonds formed in
the products, so the reaction requires more energy
Reactants absorb energy from
surroundings.
5 Examples of Endothermic Reaction
Following are the examples of endothermic reactions:-
1. Photosynthesis: - Green plants prepare food from CO2 and water in the presence of sunlight. So this is an endothermic reaction.
2. Melting of ice:- Ice absorbs heat energy from the surrounding area and starts melting.
3. Dissolution of NH4Cl in water:- Ammonium chloride is a crystalline substance, when it is added to water, it dissociates in water in the ammonium and chloride ions.
The solution absorbs heat from the surrounding and becomes cold, so this is an endothermic reaction.
4. Dissolution of sugar in water:- When sugar is added to water, the solution becomes cold as it absorbs heat from surroundings. This is an endothermic reaction.
5. Evaporation of water:- Water absorbs heat energy from its surroundings and the kinetic energy of water molecules increases and water gets converted into vapour. The conversion of liquid into vapour is called evaporation.
Related Topics
1. What happens during a chemical reaction
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