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

The leak also depletes the source for a chemical reaction, which is generating heat that, in turn, accelerates the reaction in a process called “thermal runaway.”

From Los Angeles Times • May 24, 2026

In other words, continuing to cool the tank could slow the chemical reaction in a way that avoids an explosion.

From Los Angeles Times • May 23, 2026

Workers at Catalyst Refiners Inc. in Institute, W.Va., were cleaning and decontaminating a metal processing site—in preparation for closing it down—when a chemical reaction created dangerous hydrogen sulfide gas around 9:30 a.m.

From The Wall Street Journal • Apr. 22, 2026

Every chemical reaction must overcome an energy hurdle before it can occur.

From Science Daily • Mar. 20, 2026

“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