Between the examples of chemical energy we can find batteries, biomass, oil, natural gas or coal. Chemical energy is the energy stored within chemicals, which makes it energy within atoms and molecules..
Most of the time, it is considered the energy of chemical bonds, but the term also includes energy stored in the electronic arrangement of atoms and ions..
It is a form of potential energy that will not be observed until a reaction occurs. Generally, once chemical energy is released from a substance, it transforms into a completely new substance..
For thousands of years wood has been a source of energy. Around a campfire, the wood burns and as the wood burns, the chemical energy stored in the bonds of the cellulose molecules in the wood releases heat and light..
During the Industrial Revolution, steam engines, such as trains, used coal as a source of energy.
When coal burns, it releases heat that was used to evaporate water and produce kinetic energy with the movement of a piston..
Although steam engines are no longer in use today, coal is still used as a source of energy to generate electricity and heat..
Liquid fuels such as oil or gas are some of the most economically important forms of chemical energy for human civilization..
When an ignition source is provided, these fossil fuels are instantly transformed, releasing a tremendous amount of energy in the process..
That energy is harnessed in many ways, particularly for transportation purposes.
When you step on the accelerator of your car, the gas in the tank is converted into mechanical energy that propels the car forward, which then creates kinetic energy in the shape of the moving car..
When propane gas is burned for cooking on a grill, the chemical energy stored in the bonds of the propane molecules is broken and the heat is released for cooking..
In the same way, natural gas, such as methane, is being used as an alternative to gasoline and diesel to power vehicles.
Chemical elements have the ability to give up or accept electrons. By doing so, they remain in a state of greater or lesser energy depending on the element..
When one element transfers one electron to another, the difference between these energy states is called the redox potential..
By convention, if the difference is positive then the reaction occurs spontaneously.
The oxidation potential is the foundation that batteries work with. When an element gives an electron to another, it travels through a wire producing electrical energy which powers electronic devices such as cell phones, remote controls, toys, etc..
There are some species, such as electric eels (electrophorus electricus) or abyssal fish (melanocetus johnsonii) that are capable of generating bioelectricity externally.
In fact, bioelectricity is present in all living things. Examples of these are membrane potentials and the neuronal synapse..
During photosynthesis, the energy in sunlight is converted into chemical energy that is stored in the bonds of carbohydrates..
Plants can then use the energy stored in the bonds of carbohydrate molecules for growth and repair..
The food that people eat, whether from a plant or an animal, is a form of stored chemical energy that bodies use to move and function..
When food is cooked, some of the energy is released from its chemical bonds as a result of the heat energy that is applied..
After people eat, the digestive process further transforms chemical energy into a form that their bodies can use..
During cellular respiration, our bodies take in glucose molecules and break the bonds that hold the molecules together..
When these bonds are broken, the chemical energy stored in these bonds is released and used to make ATP molecules, a form of energy usable for us..
Muscle movement is an example of how the body uses chemical energy to transform it into mechanical or kinetic energy..
When using the energy contained in ATP, conformational changes occur in the proteins of the skeletal muscle causing them to tense or relax, causing physical movement..
When living things die, the energy contained in their chemical bonds must go somewhere. Bacteria and fungi use this energy in fermentation reactions..
Hydrogen is a light and flammable gas. When combined with oxygen, it releases heat explosively.
This was the cause of the Hindenburg airship tragedy since these vehicles were inflated with hydrogen. Today this reaction is used to propel rockets that go into space..
Explosions are chemical reactions that happen very fast and release a lot of energy. When an explosive is fired, the chemical energy stored in the explosive changes and is transferred to sound energy, kinetic energy, and thermal energy..
These are observable in the sound, movement and heat that are created.
Neutralizing an acid with a base releases energy. This is because the reaction is exothermic..
Also, when an acid is diluted in water, an exothermic reaction occurs. Great care must be taken when doing so to avoid splashing the acid. The correct way to dilute an acid is to always add it to water and never the opposite..
Cold containers used in sports are examples of chemical energy. When the inner bag that fills with water breaks, it reacts with the ammonium nitrate granules and creates new chemical bonds during the reaction, absorbing energy from the environment..
As a result of the chemical energy being stored in new bonds, the temperature of the cold container decreases.
These helpful bags used to warm cold hands or sore muscles have chemicals inside of them.
When you tear the package apart to use it, the chemicals are activated. These chemicals mix and the chemical energy they release creates the heat that warms the package..
In a chemical reaction in a laboratory: aluminum foil is added to the hydrochloric acid solution.
The test tube gets very hot because many chemical bonds are broken during the reaction releasing chemical energy causing the temperature of the solution to rise.
Despite not being an example of chemical energy, it is worth mentioning. When a nucleus fission, it splits into several smaller fragments.
These fragments, or fission products, are roughly equal to half the original mass. Two or three neutrons are also emitted.
The sum of the masses of these fragments is less than the original mass. This "disappeared" mass (about 0.1% of the original mass) has been converted into energy according to Einstein's equation.
Chemical reactions involve the making and breaking of chemical bonds (ionic and covalent) and the chemical energy of a system is the energy released or absorbed due to the making and breaking of these bonds..
Bond breaking requires energy, bonding releases energy, and the overall reaction can be endergonic (ΔG <0) o exergónica (ΔG> 0) based on the general changes in the stability of the reagents to the products (Chemical Energy, S.F.).
Chemical energy plays a crucial role in every day of our life. Through simple reactions and redox chemistry, breaking and bonding, energy can be extracted and harnessed in a usable way.
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