1. Thermodynamic properties of the gas phase

The gaseous state is characterized by a low atomic or molecular density (of the order of 2 x 10 ²⁵ atoms per cubic meter, whereas in the condensed phase – solid or liquid- it is of the order of 6 x 10 ²⁸ atoms per cubic meter) under normal pressure and temperature conditions (P = 1 bar and T = 25°C) . In a gas, the average distance covered by a particle moving between two successive impacts (collisions) is around ten times greater than the size of the molecules. A gas is generally composed of atoms with...