%N= masa N : mase N[tex]{2}[/tex]0 * 100%
mN[tex]{2}[/tex]0= 14u * 2 + 16u = 44u
%N = [tex]\frac{28}{44}[/tex] * 100 = 63,6%
%O = 100% - 63.6% = 36,4%
