Percent Composition Example:

Calculate the percent composition of Mg(NO3)2
1Mg = 1 x 24 = 24
2N = 2 x 14 = 28
6O = 6 x 16 = 96
148g/mole
%Mg = 24/148 x 100 = 16.2%
%N = 28/148 x 100 = 18.9%
%O = 96/148 x 100 = 64.0%