The molecular weight of ammonia is 17.03052 grams per mole. To compute the molecular weight, the atomic weights of all the atoms in the ammonia molecule are added together.
One molecule of ammonia (NH3) is made up of one atom of nitrogen and 3 atoms of hydrogen. From the periodic table, the listed atomic weights of nitrogen and hydrogen are 14.0067 grams per mole and 1.00794 grams per mole respectively. To compute for the molecular weight, the atomic weights of one atom of nitrogen, which is 14.0067 grams per mole, and 3 atoms of hydrogen, which is 1.00794 grams per mole multiplied by 3 or 3.02382 grams per mole should be added. The answer to the equation is 17.03052 grams per mole.