The molar mass of H2, which is the chemical formula for dihydrogen, is 2.01 grams per mole with a standard deviation of plus or minus 0.00014 grams per mole. The molar mass is determined by combining the atomic weight of all the atoms in the compound.
Each atom of hydrogen has an atomic weight of 1.01 grams per mole. Since there are two atoms of hydrogen in dihydrogen, its molar mass is equal to 1.01 plus 1.01 grams per mole. Molar mass is a physical property of single atoms or compounds and is frequently used in chemistry, although it is also used in physics.