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.