History of chemistry 1808, certain of his central ideas were soon adopted by most chemists. However, uncertainty persisted for half a century about how atomic theory was to be configured and applied to concrete situations; chemists in different countries developed several different incompatible atomistic systems. A paper that suggested a way out of this difficult situation was published as early as 1811 by the Italian physicist Amedeo Avogadro (1776-1856), who hypothesized that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules, from which it followed that relative molecular weights of any two gases are the same as
Base conditions Base conditions Base conditions, also known as standard conditions, consist of a specified absolute pressure and temperature. To ensure accuracy, it is important to refer to base conditions when measuring the volume of a sample of liquid or gas. This applies to both static measurement and flow measurement. The density of both gases and liquids depends on the pressure and temperature of the fluid. Thus volumes measured in cold conditions or in pressurised conditions will be lower than the same mass of fluid at warmer or depressurised conditions. This fact gives rise to the necessity of choosing a benchmark pressure