C1.1.1.2 Determination of the Molar Mass of GasesDetermination of the Molar Mass of Gases At constant pressure and constant temperature, any gas occupies the same volume regardless of the type of atom or the composition. So if we know the volume, pressure and temperature, we can then determine the molar mass of gases. The measurement is conducted in experiment C1. 1. 1. 2 with a glass sphere for weighing gases. Components of experiment: 1 379 07 Sphere with 2 stopcocks, glass, 1 l 1 OHSPU123