combining-volumes principle

combining-volumes principle

[kəm¦bīn·iŋ ¦väl·yəmz ‚prin·sə·pəl]
(chemistry)
The principle that when gases take part in chemical reactions the volumes of the reacting gases and those of the products (if gaseous) are in the ratio of small whole numbers, provided that all measurements are made at the same temperature and pressure. Also known as Gay-Lussac's law of volumes.