ˌchemical reˈaction BrE AmE noun [uncountable and countable]
a natural process in which the atoms of chemicals mix and arrange themselves differently to form new substances:
the chemical reaction between ozone and chlorine
ˌchemical reˈaction BrE AmE noun [uncountable and countable]
a natural process in which the atoms of chemicals mix and arrange themselves differently to form new substances:
the chemical reaction between ozone and chlorine
Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012