What is Chemical Energy?

Chemical Energy

• Chemical energy is defined as energy stored in the bonds of chemical compounds.
• Examples of chemical energy include alkaline batteries, gasoline, coal, and the foods we eat.
• Chemical energy is a form of potential energy, which is stored energy.

How Chemical Energy Works

• Breaking bonds between atoms requires energy, while forming new bonds releases energy.
• The energy released during the formation of new bonds is greater than the energy required to break the original bonds.
• This process is useful for extracting energy from chemical compounds.

Exothermic and Endothermic Reactions

• Exothermic reactions release more energy than they require, such as the combustion of propane, gasoline, and wood.
• Endothermic reactions require more energy than they release, such as the decomposition of food in a compost pile or the use of disposable ice packs.

Chemical Energy Examples

Photosynthesis

• Plants store chemical energy within their bodies through photosynthesis.
• During photosynthesis, carbon dioxide and water are broken down and reformed into glucose molecules, releasing oxygen as a waste product.
• Photosynthesis is an endothermic reaction, requiring energy from the Sun.

Petroleum

• Petroleum is a fossil fuel formed from ancient marine organisms like algae.
• The burning of fossil fuels is an exothermic reaction, releasing excess energy and producing carbon dioxide and water molecules.

Food

• The chemical energy in food can be traced back to the Sun.
• During digestion, the bonds in food are broken and new bonds form, releasing energy in an exothermic reaction.

Batteries

• Batteries store chemical energy and transform it into electricity.
• Chemical reactions occur between the metals and electrolytes in batteries, freeing electrons and producing electricity.

Hand Warmers

• Hand warmers produce an exothermic reaction, releasing excess heat.
• The reaction occurs when oxygen reacts with iron in the pouch, forming rust and releasing more energy than was required to break the bonds in the oxygen molecules.

Learn about chemical energy, its definition, and examples of substances that contain it, such as alkaline batteries, gasoline, coal, and even the food we eat.