1) one of the basic gas laws, according to which the volume of a given mass of gas at constant pressure varies linearly with temperature: Vt=V0(1+αVt), where V0 and Vt are the volumes of the gas at the initial and the final temperature, t is the difference of these temperatures, and αV is the coefficient of thermal expansion of gases at constant pressure, approximately equal for all gases to 1/273.15 K-1. Gay-Lussac's law holds strictly for ideal gases; real gases obey it at temperatures and pressures far from the critical values. It is a particular case of the Clapeyron equation. Discovered by the French scientist J. L. Gay-Lussac in 1802.
2) The law stating that the volumes of gases entering into chemical reactions stand in simple ratios to one another and to the volumes of the gaseous products of the reaction, that is, in ratios of small whole numbers, for example 1:1:2 (the law of volume ratios). Discovered by J. L. Gay-Lussac in 1808. It played a large part in the discovery of Avogadro's law.
2) The law stating that the volumes of gases entering into chemical reactions stand in simple ratios to one another and to the volumes of the gaseous products of the reaction, that is, in ratios of small whole numbers, for example 1:1:2 (the law of volume ratios). Discovered by J. L. Gay-Lussac in 1808. It played a large part in the discovery of Avogadro's law.