The Gram Molecular Mass (GMM) of chlorine is 35.5 grams per mole. This value is derived from the atomic mass of chlorine, which is approximately 35.5 atomic mass units (amu). Chlorine exists as a diatomic molecule (Cl2), so its molecular mass is twice its atomic mass, resulting in 71 grams per mole for Cl2.
The atomic mass of chlorine is an average of the masses of its isotopes, primarily chlorine-35 and chlorine-37, weighted by their natural abundances. This averaging gives chlorine an atomic mass of 35.5 amu. When calculating the GMM for chlorine gas (Cl2), we multiply this atomic mass by 2, leading to the GMM of 71 grams per mole.
Understanding the GMM is crucial in chemistry for stoichiometric calculations, determining the amount of substance in moles, and converting between mass and moles in chemical reactions.