Question

why is respiration considered to be an exothermic reaction​

Answer 1

Answer:

It involves the burning of sugar with oxygen, within the cells of every living organism to produce the energy needed for all the reactions of life along with water and carbon dioxide as waste products. ... Respiration is another exothermic reaction.

Answer 2

Answer :

Respiration refers to the overall process by which organism is abstracted from air and is transported to cells for the oxidation of organic molecules (glucose) while carbon dioxide and water, the product of oxidation, are returned to the environment. During digestion, carbohydrates, we take as food, are broken down into glucose. When we breathe in air, the oxygen enters our lungs. It bind itself with the haemoglobin present in red blood cells and is carried to millions of cells present on the body. Here, glucose 'burns', i.e., gets oxidized to produce carbon dioxide and water be liberation of heat (energy).

Chemical reaction :

$\sf \small C_{6} H_{12} O_{6} (s) + 6O_{2} (g) \longrightarrow 6CO_{2} (g) + 6 H_{2}O(\ell) + 2820 kJ$