Answer:
It's 23.14 percent
Explanation:
First, the mass of all the elements are:
N = 14
O = 16
Fe = 56
In this molecule you have 3 atoms of N, and 9 atoms of O, so:
3•14 = 42
16•9 = 144
The whole mass of the molecule is:
56 + 42 + 144 = 242
242/100 = 2.42, so 1% is 2.42
56/2.42 = 23.14%
