chemical reaction

American  

[kem-i-kuhl ree-ak-shuhn] / ˈkɛm ɪ kəl riˈæk ʃən /

noun

1. Chemistry. reaction.

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chemical reaction British  

noun

1. a process that involves changes in the structure and energy content of atoms, molecules, or ions but not their nuclei Compare nuclear reaction

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chemical reaction Cultural  

1. A process in which atoms of the same or different elements rearrange themselves to form a new substance. While they do so, they either absorb heat or give it off.

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Etymology

Origin of chemical reaction

First recorded in 1780–90

Example Sentences

Hydrogen sulfide smells like rotten eggs and can be produced by a chemical reaction and by some organic material, such as sewage.

From The Wall Street Journal • Apr. 22, 2026

The crystals are driven by a chemical reaction similar to the one used to power rockets.

From Science Daily • Mar. 19, 2026

Form’s iron-air batteries generate electricity through a chemical reaction involving oxygen, water and iron powder that mimics how old pieces of metal gather rust.

From Barron's • Feb. 24, 2026

The smoldering chemical reaction inside Chiquita Canyon Landfill is growing and could last for decades, according to a new state analysis.

From Los Angeles Times • Nov. 19, 2025

“You’ve smelled rotten eggs? That’s sulfur dioxide, released from the chemical reaction of rotting organic material. This is going to stink just like that.”

From "October Sky" by Homer Hickam

Related Words

• vicious circle