chemical reaction

American  

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

noun

1. Chemistry. reaction.

---

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

---

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.

---

Etymology

Origin of chemical reaction

First recorded in 1780–90

Example Sentences

See Examples For:

chemical reaction

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

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

“Pressure brings it up. It results from a chemical reaction in the lungs when water mixes with air and mucus.”

From "Snow Falling on Cedars: A Novel" by David Guterson

Related Words

• vicious circle