Exothermic Reaction:
An exothermic reaction is a chemical reaction that releases energy in the form of heat. This means that the overall energy of the system decreases as the reaction proceeds. Exothermic reactions are characterized by a rise in temperature in the surroundings.
- Example: Combustion of fuel such as wood or gasoline is an exothermic reaction. When wood burns, it reacts with oxygen in the air to produce carbon dioxide and water vapor, releasing heat in the process.

Endothermic Reaction:
An endothermic reaction is a chemical reaction that absorbs energy from its surroundings, usually in the form of heat. This means that the overall energy of the system increases as the reaction proceeds. Endothermic reactions are characterized by a decrease in temperature in the surroundings.
- Example: The reaction between ammonium nitrate and water is an endothermic reaction. When these two substances are mixed, they absorb heat from the surroundings to break the bonds between their molecules, resulting in a decrease in temperature.
In conclusion, exothermic reactions release energy in the form of heat, while endothermic reactions absorb energy from the surroundings. Both types of reactions play a crucial role in various chemical processes and are essential for understanding the principles of thermodynamics.