In an exothermic reaction, internal energy of reactants is greater than internal energy of the products and therefore, change in the energy will be negative. It is represented as

Reactants + Energy $\to$ Products

In an endothermic reaction, the internal energy of reactants is less than the internal energy of the products. It is represented as

Reactants $\to$ Products + Energy

  Energy released or absorbed is measured in kilocalories or kilojoules.

1. Is it true that in an exothermic reaction

• reactants + energy forms products or will it be
• reactants form products and energy ?

2.  Please explain the graph in the context

 

Dear student
Please find the solution to the asked query:

Bond energy of reactants is less than the bond energy of products means that the energy stored in the bonds of reactants is less than the energy stored in bonds of products.
This means that the amount of energy released in the formation of product bonds is more than the amount of energy required to break the bonds of reactants. 
 Therefore energy is released and the reaction becomes exothermic .
So reactants break down to give products + energy.


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