Question

Give an example of a chemical change in which heat is liberated.

Answer 1

Exothermic reactions:

The reactions in which heat is released in the form of heat and light to the surroundings are called exothermic reactions.

Example of a chemical change in which heat is liberated:

When coal (C) is burnt in the presence of Oxygen $\left({\mathrm{O}}_2\right)$ then heat is liberated and Carbon dioxide $\left({\mathrm{CO}}_2\right)$ is formed. The chemical reaction is as follows:

$$\begin{gathered} \mathrm{C}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to {\mathrm{CO}}_2\left(\mathrm{g}\right)+\mathrm{Heat}+\mathrm{Light} \\ \mathrm{Carbon}\mathrm{Oxygen}\mathrm{Carbon} \\ \mathrm{dioxide} \end{gathered}$$