A chemical system is any combination of chemical components under observation. A solution of salt in water , for example, is a chemical system in which the components are salt and water. The chemical components of a system can exist as gas , liquid , or solid phases. The phase rule is applicable only to systems, called heterogeneous systems, in which two or more physically distinct phases are in equilibrium. A system cannot contain more than one gas phase but can contain any number of liquid and solid phases.
Water is an example of a heterogeneous chemical system of one component.
The liquid and gas phases, water and water vapor, coexist over a wide range of temperature s and pressure s. C represents the number of chemical components of the system and P the number of phases present. The rule makes possible the simple correlation of very large quantities of physical data and the prediction, to a limited extent, of the behavior of chemical systems. It is applied in the solving of many practical problems, particularly in the field of metal-alloy preparation and in chemical engineering, and is also useful to geologists. All Rights Reserved Worldwide.