1. Molar, mass and volume quantities

A thermodynamic property is related to a quantity of matter, which is either the mole, the unit of mass or the unit of volume.

• Remember that the molar mass of a substance M is the mass, expressed in grams, of 6.022 05 × 10 ²³ molecules (Avogadro's number, N = 6.022 05 × 10 ²³ mol ^–1 ).

  Example

  normal heptane has a molar mass M = 100. This means 100 g · mol ^–1 or 100 × 10 ^–3 = 0.1 kg · mol ^–1 (or 100 kg · kmol ^–1 ).

• ...