A mixture in a fluid state (liquid, gas or supercritical fluid).
The mixture components (which are pure substances) in this case are called Fluid Components.
A list and molar fractions of all fluid components constituting a fluid mixture is called Fluid Composition.
Unlike pure substances the fluid mixtures in a state of Thermodynamic equilibrium may see liquid and gas phases occupy a continuous area in PT Diagram (see also Vapour Liquid Equilibrium).
The mass fraction of liquid and gas phases is also called Liquid Quality and Vapour Quality correspondingly.
Natural Science / Chemistry / Chemical Substance / Mixture
[ Pure substance ][ Liquid Quality ]][ Vapour Quality ]
[ Vapour Liquid Equilibrium (VLE) ]