Question

Why is respiration considered an exothermic reaction? Explain.

Answer 1

Hint: Exothermic reactions are reactions in which heat is released. It is a process in which energy is released in the form of heat. Respiration involves energy release.

Complete step by step solution:
- The movement of oxygen from the outside environment to the cells in the tissues and the movement of carbon dioxide in the opposite direction. By respiration, an organism obtains energy by oxidising nutrients and it releases waste products.
- Exothermic reaction is a reaction in which energy is released in the form of heat. When digestion occurs in our body, the food particles are broken down to simpler molecules through a series of reactions. Food particles can be carbohydrates, proteins, fats etc. Taking the example of a carbohydrate that is present in the food, it is broken down into simpler substances, such as glucose and fructose. This glucose then reacts with the oxygen present and gives carbon dioxide and water. Both are released in gas form and evolve heat.
- Respiration can also be released as a special form of burning a fuel. The food containing carbohydrates are the fuel for organisms and through the respiration process; it is broken down to simpler molecules evolving heat, providing this energy for all the reactions of life along with water and carbon dioxide. This is why when we breathe out, our breath is warmer.
\[\underset{{}}{\mathop{Glu\cos e}}\,+oxygen\to energy+C{{O}_{2}}+water\]
Thus, we can conclude that the respiration process is an exothermic reaction.

Note: Respiration can also be related as a combustion reaction, as it breakdowns an organic molecule to carbon dioxide and water. Along with this energy is also released.