To solve this if you find out how many mol of N2O you can multiply that by 2 to find the mol of N. There are 2 N for every one molecule of N2O.
To do this, you can use the Atomic Mass Unit of the atoms to find the mol. 1 mol of hydrogen has weights 1 gram, hydrogen has an atomic mass unit of 1. Atomic mass unit shorthand is amu.
For molecules, if you take the total of amu for each atom in the molecule and add them together you will have the weight of the molecule in amu.
The amu can be converted into how many grams are in one mole.
N is nitrogen which has an amu of 14.
O is oxygen which has an amu 16
2 * 14 + 16 = 44 amu
1 mol of N2O is 44 grams.
0.161g / 44 g / mol = 0.00366 mol of N2O
There is 2 N in each mol of N2O which means that 0.00366 mol * 2 = 0.00732 mol of N
There are 0.00732 mol of N in 0.161g of N2O