1.Molar mass is the mass of one mole per single element while atomic mass is the mass of an atom at rest or is the number of protons and neutrons.
2.Molar mass is measured in grams per mole while atomic mass is “unitless.”
3.Atomic mass is measured via mass spectrometry while molar mass is computed via atomic weight.
Gas molecules have more freedom in motion—and gases can be thought of as more “disordered”—than molecules of a solid, which are rigidly held in place. When it comes to phases, the entropy increases as you go from a solid to liquid to gas (the gaseous state having the greatest entropy and the solid state having the least).
So, as a sample of solid iodine sublimes to form gaseous iodine, the entropy of the sample increases.