Search results
Results from the Think 24/7 Content Network
Combustion ( fire) was the first controlled chemical reaction discovered by humans, in the form of campfires and bonfires, and continues to be the main method to produce energy for humanity. Usually, the fuel is carbon, hydrocarbons, or more complicated mixtures such as wood that contain partially oxidized hydrocarbons.
Exothermic reaction. 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 Δ H ⚬ is negative." [1] [2] Exothermic reactions usually release heat.
In thermodynamics, an exothermic process (from Ancient Greek έξω (éxō) 'outward' and θερμικός (thermikós) 'thermal') [ 1] is a thermodynamic process or reaction that releases energy from the system to its surroundings, [ 2] usually in the form of heat, but also in a form of light (e.g. a spark, flame, or flash), electricity (e.g ...
A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. [ 1] When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an energy change as new products are generated. Classically, chemical reactions encompass changes that only involve the positions ...
Spontaneous combustion or spontaneous ignition is a type of combustion which occurs by self-heating (increase in temperature due to exothermic internal reactions ), followed by thermal runaway (self heating which rapidly accelerates to high temperatures) and finally, autoignition. [ 1] It is distinct from (but has similar practical effects to ...
Heat of combustion. The heating value (or energy value or calorific value) of a substance, usually a fuel or food (see food energy ), is the amount of heat released during the combustion of a specified amount of it. The calorific value is the total energy released as heat when a substance undergoes complete combustion with oxygen under standard ...
In the Arrhenius model of reaction rates, activation energy is the minimum amount of energy that must be available to reactants for a chemical reaction to occur. [1] The activation energy ( Ea) of a reaction is measured in kilojoules per mole (kJ/mol) or kilocalories per mole (kcal/mol). [2] Activation energy can be thought of as the magnitude ...
The fire triangle or combustion triangle is a simple model for understanding the necessary ingredients for most fires. [1] The triangle illustrates the three elements a fire needs to ignite: heat, fuel, and an oxidizing agent (usually oxygen ). [2] A fire naturally occurs when the elements are present and combined in the right mixture. [3]