One type of energy is chemical energy, the energy that is created or released in a chemical reaction.
Chemical Energy: Storage and Release
Chemical energy is stored in the chemical bonds of atoms and molecules. It can only be seen when it is released in a chemical reaction. When chemical energy is released, the substance from which the energy came is often changed into an entirely different substance.
Many substances and objects store and release chemical energy:
- Batteries – You can connect a battery to a circuit and a reaction between chemicals takes place inside the battery and it produces electricity. You cannot see the energy in the battery when the battery is just sitting around; it is when the electricity is produced that the energy is seen.
- Petroleum – A combination of oil and natural gas, petroleum is made of hundreds of molecules containing carbon and hydrogen.
- When petroleum is a vapor it is natural gas.
- When petroleum is a liquid it is crude oil.
It can be used to create electricity and heat and can be found in propane, jet fuel, gasoline and other products.
- Wood – Dry wood stores chemical energy. This chemical energy is released as the wood burns, and it is converted into heat, which is also called thermal energy, and light energy. As a result of burning, the wood turns into an entirely new substance – ashes.
- Explosives – When an explosive goes off, chemical energy that was stored in the explosive is changed and transferred into sound energy, kinetic energy, and thermal energy. These are observable in the sound, motion, and heat that are created.
- Food – The chemical energy in food is released while the food is being digested and the molecules of food are broken down into smaller pieces. As the bonds between the atoms of the food break or loosen, new substances are created as a result of the chemical reactions taking place.
- Bleach and ammonia – When these two substances are mixed, an entirely new substance – a toxic chemical called chloramines vapor – is produced.
- Heating packs – These handy packages that are used to warm up cold hands or sore muscles have chemicals inside of them. When you crack the pack to use it, chemicals are activated. These chemicals mix together, and the chemical energy that they release creates the heat that warms up the pack.
- Vehicle air bags – The bags are activated by a chemical reaction inside the bag. A sensor turns on an electrical circuit, and then sodium azide is ignited. The reaction that occurs generates nitrogen gas, which fills the bag at an extremely rapid rate.
- Baking soda and vinegar – When these two substances are mixed in a container, carbon dioxide gas is produced. As this gas grows in volume, it puts pressure on whatever container it is in, and will erupt out of an opening in the container, creating a volcano effect.
As these examples show, there is lots of stored chemical energy in objects you interact with every day.