Question

State the types of change involve when there is a change of energy by giving a proper example.

Answer 1

• The physical and chemical changes are always accompanied by changes in energy.
• The energy can be absorbed or released during the change.
• Depending upon the involvement or evolution of energy, the changes can be classified into the category of endothermic and exothermic reactions.
• Exothermic reactions involve the release of energy during the change.
• Endothermic reactions involve the use of energy to perform the reactions.

Example- When a small quantity of Calcium oxide ( $\mathrm{CaO}$) is dissolved in water in a beaker. The beaker becomes hot because energy is getting released during the process. It is a chemical change accompanied by the release of energy. So, it is an exothermic reaction.