Question

How to calculate the molecular mass of Nh4No3

Answer 1

Add up the atomic weight of all the constituent atoms: 2N, 4H, 3O
(no, I'm not going to do it for you)

Because atomic weights are in moles per gram, adding them all up gives you the sum of all the atom moles, which is of course the same as the molecular weight (that's what a molecular weight is)

Answer 2

The molar mass of ammonium nitrate is 80.04336 g/mol.

The molar mass of nitrogen is 14.0067 g/mol. There are two nitrogen atoms in this compound so we multiply nitrogen's molar mass by 2.(2)(14.0067 g/mol) = 28.0134 g/molThe molar mass of hydrogen is 1.00794 g/mol. There are four hydrogen atoms in the compound.(4)(1.00794 g/mol) = 4.03176 g/molThe molar mass of oxygen is 15.9994 g/mol. There are three oxygen atoms in the compound.(3)(15.9994 g/mol) = 47.9982 g/mol