# How is the molar weight of C-12 equal to 12 gram ? Why is "g" not considered while calculating molar weight? [closed]

So, I was just pretty confused about how we simply multiply the "mass" of total nucleons in Carbon by the Avogadro Constant, to get the molar "weight" as 12 grams, shouldn't it be the molar "mass", as we have not considered the effect of g anywhere ?

• Technically, it is mass. But, since the calculations aren't changed by using weight instead of mass (g, the acceleration due to gravity, is just a constant multiplier), "molecular weight" and "molecular mass" are often used interchangeably, where it's understood that "weight" means "weight under earth gravity". But, yes, using "mass" would be more technically precise. Essentially, it's no different from laboratory scales expressing their weight readouts as a mass (typically grams), when what they are really measuring is a force, which should instead be expressed in newtons. Jun 24 '21 at 5:01
• 2 g hydrogen atoms (H): $\frac{2 g}{1 g/mol}= 2\, mol$. 2 g hydrogen gas ($\ce{H_2(g)}$): $\frac{2 g}{2 g/mol}= 1 \,mol$. Jun 24 '21 at 5:43
• You are confused by the usage of the words, mass and weight. Try searching for their definitions. Jun 25 '21 at 3:17