Do not round them further when performing calculations. All average masses are to quantities, and subject to significant figure rules. The molar mass of a compound is the mass in grams of 1 mole of that substance, a property expressed in units of grams per mole (g/mol)īecause the definitions of both the mole and the formula mass are based on the same reference substance, 12C, the molar mass of any compound is numerically equivalent to its formula weight in amu. The Periodic Table of the Elements 1 18 Hydrogen 1 H 1.01 2.1 be treated as measured 2 Average relative masses are 2001 values, rounded to two decimal places.
The molar mass of the N 2 molecule is therefore 28.02 g/mol. This is referred to as the molecular mass and the molecular mass of any molecule is simply the sum of the atomic masses of all of the elements in that molecule. The masses of 1 mole of different compunds, however, are different, since the masses of the individual molecules are drastically different. For nitrogen, the mass of the N 2 molecule is simply (14.01 + 14.01) 28.02 amu. Interactive periodic table with up-to-date element property data collected from authoritative sources. Add them together: add the results from step 3 to get the total molar mass of the compound. Calculate molar mass of each element: multiply the atomic mass of each element by the number of atoms of that element in the compound.
Similar to atoms, 1 mole of any compound contains the same number of molecules as 1 mole of any other compund. The atomic mass is usually found on the periodic table and is given in atomic mass units (amu).