What is released during the complete oxidation of a substance?

During the complete oxidation of a substance, the process is known as combustion. In this process, the substance reacts with oxygen, resulting in the release of energy in the form of heat. This specific heat released is termed the "heat of combustion."

Combustion involves breaking down the chemical bonds in a fuel and forming new bonds in the products, typically carbon dioxide and water, while producing energy. This transformation is exothermic, meaning it releases energy into the environment, making the heat of combustion a key concept in understanding fire behavior and energy release during a fire.

The other types of heat mentioned, such as heat of expansion, heat of decomposition, and heat of vaporization, refer to different processes and systems. Heat of expansion is related to the increase in size of materials when heated, heat of decomposition involves the breakdown of a substance into simpler compounds or elements, and heat of vaporization concerns the energy required to convert a liquid into a vapor. These processes do not specifically pertain to the oxidation and energy release associated with combustion.