Chemical energy refers to the energy contained within, or produced through molecular reactions of one or more compounds . It is the internal energy that a body or substance possesses, and depends on the number and type of chemical bonds between its compounds.
It is considered a type of potential energy because it is associated with matter and its modifications, which can occur in the presence of thermal energy or other substances that make it react chemically; their reaction is usually to produce heat or light.
A clear example of this is combustion , starting from a fuel ( gasoline ) that is exposed to heat, reacts chemically, and thanks to this, an engine runs ; Another clear example is the combustion of wood , which is used to release heat.
What is chemical energy?
Chemical energy is another way that energy is transformed . It is found inside bodies or objects and becomes evident when there is a significant alteration of matter. Briefly, it can be defined as the energy that is produced due to chemical reactions.
These chemical processes give off heat in the reaction. They can even develop some movement or work due to the violence that chemical reactions manifest. Thus, this energy always transforms the matter where it was contained.
How does chemical energy work?
The operation of this energy is given by chemical reactions that are accompanied, either by a release or an absorption of energy . Atoms and molecules are involved, there is a reorganization of electrons and protons to produce electrical charges.
The energy that is released or absorbed can take the form of electrical , light, mechanical energy , etc., but the most common form is through heat. These chemical reactions can be classified as exothermic or endothermic, according to whether there was a release or absorption of heat, respectively.
On the other hand, the heat that is exchanged is known as the heat of reaction and its value is specific to each reaction. All matter has stored chemical energy, known as its energy content . Chemical energy always transforms or changes matter where there was previously kinetic energy .
Characteristics of chemical energy
- It is contained within matter.
- When a chemical reaction occurs, there is a transformation of matter into another new compound.
- There may be heat release or absorption .
- It is a reaction that occurs between the atoms that make up matter.
- Bonds between atoms are broken and remade into new substances .
- If no chemical reaction occurs, chemical energy is not released or absorbed.
- Thermally, they are usually very efficient.
- It has no return ; once a reaction has taken place (a piece of wood has been burned), it cannot be returned to the original state.
examples of chemical energy
Below are some examples of chemical energy, each manifesting transformation of matter due to chemical process.
- Photosynthesis: Plants take energy from the chemical reactions that occur within them. The sun, CO2, enzymes and organic substances that obtain oxygen and energy participate. This energy is the result of the chemical reaction contained within the molecules of the acting substances. The plant releases this energy for its benefit and vital maintenance.
- Respiration: Similar to the previous example, animals use oxygen and glucose. For the cycle to be maintained, it is necessary to release water, CO2 and energy is obtained. Through this chemical process the animal kingdom is kept alive, including human beings.
- Combustion: When a vehicle’s engine is started, the hydrocarbon used as fuel undergoes a sequence of controlled ignitions and detonations that allows movement to take place. The fuel stores energy in carbon and hydrogen atoms. Once they break, they are transformed into different compounds and energy is released.
- Decomposition: Bacteria, fungi and microorganisms that take the decomposed organic matter as food obtain the energy required for the fermentation of starches and sugars. Alcohols or any other product generated by the breakdown of organic molecules are obtained from this chemical reaction.
- Batteries and cells: The batteries that are used so much in controls, cell phones or cars have acids and metals that cause a controlled chemical reaction. The result is an amount of electricity that can be used immediately.
- Nuclear energy :Despite being a completely separate branch and a form of energy as such, it can be said that it is part of chemical energy. The origin of nuclear reactions is in a series of chain reactions caused by man. This occurs in elements manipulated in the laboratory, such as uranium and hydrogen. These are chemically forced to fission or fuse the atoms, releasing huge amounts of energy.
Relationship between chemical energy and biomass
We know that biomass is the unit of matter that is stored / accumulated in individuals or biological populations such as wood, agricultural residues, etc.
In addition, we know that biomass as such is the use of said energy (otherwise it would only be organic waste), and to take advantage of it, chemical energy is usually used ; In other words, wood is nothing more than organic waste that does not pollute, but inside it has accumulated energy, therefore we will use it as fuel to run other machines. Biomass is making use of said accumulated energy through chemical processes .