In which compound the mass fraction of nitrogen is greater, in NH3 or NO2.

The mass fraction of an element in a chemical compound shows what part of the total mass of a molecule is the mass of all atoms of a particular element. It is found by the ratio of the sum of the masses of the atoms of an element to the molar mass.

w = (n * Ar) / Mr where n is the number of atoms of an element in a molecule, Ar is the relative atomic mass of the element, Mr is the relative molar mass.

From the listed substances (NH3 and NO2), at first glance, it can be assumed that the mass fraction of nitrogen is greater in the ammonia molecule, because the relative atomic mass of hydrogen is much less than the relative atomic mass of oxygen, which means that the mass fraction of hydrogen in the compound will be low. Let us confirm this assumption by calculations:

1) mass fraction of nitrogen for NH3. Mr (NH3) = 17, Ar (N) = 14

w ‘= (1 * 14) / 17 = 0.82

2) mass fraction of nitrogen for NO2. Mr (NO2) = 46, Ar (N) = 14

w “= (1 * 14) / 46 = 0.30

As can be seen from the calculations, the mass fraction of nitrogen in nitrogen hydride is much higher.