Question

This graph shows the energy involved in a reaction involving two molecules. Describe what is happening or what the state of the reaction is at A, B, C, and D. Then tell if this is an exothermic or an endothermic reaction.

Answer 1

Answer : A = reactant, B = activated complex, C = product, D = activation energy.

This is an exothermic reaction.

Explanation :

Activated complex : When the reactant molecules absorb energy, their bonds are loosened and new lose bonds are formed between them. The intermediate thus formed is known as activated complex or transition state. It is unstable state and immediately dissociates to form the stable products.

Activation energy : It is defined as the minimum amount of energy absorbed by the reactant molecules so that their energy becomes equal to the threshold energy.

Endothermic reaction : It is a type of chemical reaction where the energy is absorbed from the surrounding. In the endothermic reaction, the reactant are less than the energy of product.

Exothermic reaction : It is a type of chemical reaction where the energy is released into the surrounding. In the exothermic reaction, the energy of reactant are more than the energy of product.

Hence, in the given energy graph, A = reactant, B = activated complex, C = product, D = activation energy. This is an exothermic reaction.