17.1: Chemical Potential Energy

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Gunpowder was originally developed by the Chinese in the ninth century AD, primarily for rockets. This material is composed of charcoal, sulfur, and saltpeter (potassium nitrate). The explosive reaction that occurs involves the conversion of the charcoal to carbon dioxide, with the potassium nitrate providing the extra oxygen needed for a rapid reaction. Although sulfur was included to stabilize the product, gunpowder is still highly explosive.

Types of Energy

Two basic types of energy exist: potential energy and kinetic energy. Potential energy is stored energy. It has not yet been released, but is ready to go. Kinetic energy is the energy of motion. It causes work to be done through movement.

Chemical Potential Energy

Energy is the capacity for doing work or supplying heat. When you fill your car with gasoline, you are providing it with potential energy. Chemical potential energy is the energy stored in the chemical bonds of a substance. The various chemicals that make up gasoline contain a large amount of chemical potential energy that is released when the gasoline is burned in a controlled way in the engine of the car. The release of that energy does two things: some of the potential energy is transformed into work, which is used to move the car; at the same time, some of the potential energy is converted to heat and makes the car's engine very hot. The energy changes of a system occur as either heat or work, or some combination of both.

Race Car on race track burning tire, smoke coming from tire. — Figure \(\PageIndex{1}\): A dragster is able to accelerate because of the chemical potential energy of its fuel. The burning of the fuel also produces large amounts of heat. (CC BY-NC; CK-12)

Dynamite is another example of chemical potential energy. The major component of dynamite is nitroglycerin, a very unstable material. By mixing it with diatomaceous earth, the stability is increased and it is less likely to explode if it receives a physical shock. When ignited, the nitroglycerin explodes rapidly, releasing large amounts of nitrogen and other gases along with a massive amount of heat.

Figure \(\PageIndex{2}\): Dynamite explosion. (CC BY-NC; CK-12)

Summary

Potential energy is stored energy.
Kinetic energy is the energy of motion.
Chemical potential energy is energy available in the chemical bonds of a compound.