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The thermite reaction is famously exothermic. The reduction of iron(III) oxide by aluminium releases sufficient heat to yield molten iron. In thermochemistry, an exothermic reaction is a "reaction for which the overall standard enthalpy change ΔH⚬ is negative." [1] [2] Exothermic reactions usually release heat.
According to the IUPAC, an exothermic reaction is "a reaction for which the overall standard enthalpy change ΔH⚬ is negative". [4] Some examples of exothermic process are fuel combustion, condensation and nuclear fission, [5] which is used in nuclear power plants to release large amounts of energy. [6]
Another example involving thermochemical equations is that when methane gas is combusted, heat is released, making the reaction exothermic. In the process, 890.4 kJ of heat is released per mole of reactants, so the heat is written as a product of the reaction.
Reactions can be exothermic, where ΔH is negative and energy is released. Typical examples of exothermic reactions are combustion, precipitation and crystallization, in which ordered solids are formed from disordered gaseous or liquid phases. In contrast, in endothermic reactions, heat is consumed from the environment. This can occur by ...
Commercial heat sources for self-heating food packaging use an exothermic (heat releasing) reaction, for which there are several common formulations. These include: Quicklime aka calcium oxide, and water. Quicklime, inexpensive and readily available, is generally recognized by the FDA as safe. [2] The product of the reaction is calcium hydroxide.
The reaction is usually endothermic as heat is required to break chemical bonds in the compound undergoing decomposition. If decomposition is sufficiently exothermic, a positive feedback loop is created producing thermal runaway and possibly an explosion or other chemical reaction. Thermal decomposition is a chemical reaction where heat is a ...
Thermochemistry is useful in predicting reactant and product quantities throughout the course of a given reaction. In combination with entropy determinations, it is also used to predict whether a reaction is spontaneous or non-spontaneous, favorable or unfavorable. Endothermic reactions absorb heat, while exothermic reactions release heat ...
Van 't Hoff plot for an exothermic reaction. For an exothermic reaction, heat is released, making the net enthalpy change negative. Thus, according to the definition of the slope: =, For an exothermic reaction Δ r H < 0, so