The second step is to calculate the mass of a given element ammonium nitrate (nh4no3). we will calculate the masses of all three elements. the molar mass of each element is given below: molar mass of n: 14.0 g/mol molar mass of h: 1.0 g/mol molar mass of o: 16.0 g/mol identify the number of moles of each element present in one mole of nh4no3. # moles n: 2 # moles h: 4 # moles o: 3 calculate the mass of each element in the compound by multiplying its molar mass by the number of moles of the element present in one mole of the compound. mass n = g mass h = g mass o = g