Amagat's law

Amagat's law states that a gas mixture’s volume equals the sum of the volumes its components would occupy separately at the mixture’s temperature and pressure.

Partial molar volume: The change in a mixture’s volume when an infinitesimal amount of a component is added at fixed temperature, pressure, and composition. Amagat’s component volumes are defined by imagining each gas separately at the mixture’s temperature and pressure.
Mole fraction: The ratio of the amount of one component in a mixture to the total amount of all components. For ideal gases, each component’s Amagat volume fraction equals its mole fraction.
Gas density: The mass of a gas per unit volume under specified conditions. The law lets component amounts and molar volumes estimate mixture volume before calculating density.
Dalton's law: The ideal-gas rule that a mixture’s total pressure equals the sum of its component partial pressures. Dalton’s law sums pressures at fixed volume; Amagat’s law instead sums volumes at fixed pressure.
Ideal gas law: The equation of state relating pressure, volume, temperature, and amount of an ideal gas. For ideal gases, each component’s volume contribution follows directly from its amount at common temperature and pressure.
Gas mixture: A physical mixture containing two or more gases distributed within the same volume. Amagat’s law describes how the component contributions relate to a mixture’s total volume.
Volumetric flow rate: The volume of fluid passing a point per unit time. Component flow contributions can be summed under conditions where Amagat’s additivity is valid.
Raoult's law: The relation stating that a liquid component’s partial vapor pressure equals its mole fraction times its pure-component vapor pressure. Raoult’s law governs vapor–liquid equilibrium, not additive gas-mixture volumes.
Compressibility factor: The ratio of a real gas’s molar volume to the ideal-gas molar volume at the same temperature and pressure. It quantifies departures from ideal behavior that can make component volumes nonadditive.
Avogadro's law: Equal volumes of ideal gases at the same temperature and pressure contain equal numbers of molecules. It explains why ideal-gas component volume fractions track component mole fractions.

Linked from 2 pages

Partial pressureCompared with: It parallels Dalton’s pressure rule by assigning each component a share of a mixture property.