Uniform single-phase systems
Temperatures and enthalpies of organic compounds

Some properties characterizing the state of a system have uniquely defined total values, at the scale of the system.

For example, a system has :

• a total volume V ;

• a total internal energy U ;

• total entropy S, etc.

These quantities are extensive state quantities.

State quantities that are not extensive are intensive. They correspond to local properties, defined at each point of the system.

For example: temperature T, pressure p, density, etc.

When modeling the properties of a chemical system, it is essential to take into account two fundamental quantities of extensive properties:...