Question

why there is an energy change in chemical reaction ?

Answer 1

Dear student,
There is an energy change in a chemical reaction because chemical reactions involve the breaking of bonds and the formation of new bonds. This results in the energy changes like the release of energy in a chemical reaction or absorption of energy in a reaction.
There is the absorption of energy when chemical bonds are broken and release of energy when chemical bonds are formed.
Thus, the energy changes in a chemical reaction are due to the differences in the amount of energy stored between the products and the reactants.

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