Laura A. answered • 04/17/20
Certified PA specializing in A&P and Pre-health sciences
Hi Kenny, to calculate the molar mass of any compound, you start by calculating the molecular weight based on the values in the periodic table. Na has an atomic weight of 22.99 amu and F has an atomic weight of 18.99 amu. If you add Na + F + F that would work out to 22.99 + (2)*(18.99) amu, or approximately 23 + 2*19 amu, wihch works out to 23 + 38 = 61 amu.
1 molecule of NaF2 weighs 61 amu, therefore a mole will weigh 61 grams/mol. The simplicity of the periodic table is that the same number that indicates an atoms weight in amu also indicates the weight of a mole of that atom in g/mol. Hope this helps!
Laura A.
And to clarify, the proper term would be "mass" instead of "weight," but I often like to use more everyday terms in explaining things - hope that's not confusing!04/17/20