Question

How do I find the percentage composition of Oxygen in `N_2O_5`?

Answer 1

It is `74.1%`

Explanation:

First we find the molar mass of the entire molecule. So N is 14 and O is 16. Molar mass of `N_2O_5 = 2(14) + 5(16) =108` g/mol.

To find of the percent we take the element's mass in the molecule over the total molar mass. For `O` would be `((5*16)/108) * 100` or `100%-25.9% = 74.1%`

Answer 2

`N_2O_5` molecule contains 2 N atoms and 5 O atoms, So the molar mass of `N_2O_5` =2 x atomic mass of N +5xatomic mass of O = 2x14+5x16=108 g/mole
% of N = `2*14/108*100` =25.93
% of O =`5*16/108*100`=74.07