Question

Explain why respiration is a chemical change?

Answer 1

A chemical change is defined as a change where new components are formed from the existing components having different composition, physical and chemical properties.

Complete step by step answer: The respiration is defined as the process where the cells acquire energy in the form of ATP by inhaling oxygen and releasing carbon dioxide by the oxidation reaction of complex organic substances.
During the respiration process, the oxidation of glucose takes place.
The chemical reaction for the oxidation of glucose is shown below.
${C_6}{H_{12}}{O_6} + 6{O_2} \to 6C{O_2} + 6{H_2}O + energy$
In this reaction, one mole of glucose reacts with six mole of oxygen to give six moles of carbon dioxide, six moles of water and energy.
A chemical change is defined as a change where a new product is generated from the reactant having different properties.
Some characteristics of chemical change are shown below.
(1) Chemical change is permanent.
(2) In chemical change both the physical properties, chemical properties and the composition changes.
(3) In chemical change energy is released.
(4) The chemical change is an irreversible reaction.
In the oxidation of glucose, carbon dioxide and water are formed. As new products are formed of different composition and characteristics, the respiration is considered as a chemical change.
The respiration process is an irreversible process as glucose cannot be obtained back.

Note: The equation for the respiration is generated from three main processes glycolysis where glucose is break down into three carbon molecules (pyruvic acid), the Krebs cycle where carbon molecules releases energy and the Electron transport chain in which the oxygen is required and produces more energy in the form of ATP.