Formula masses and percent composition
of three theoretical compounds of Mg and O
Empirical Formula Example 2
2
nd
Step:
Formula Masses and their Percent Composition.
Mg = 24.31 g/mole
O = 15.999 g/mole
15.999/
64.619
2 x 24.31/
64.619
64.619
2(24.31) + 15.999
=
Mg
2
O
2 x 15.999/
56.308
24.31/
56.308
56.308
24.31 + 2(15.999)
=
MgO
2
15.999/
40.309
24.31/
40.309
40.309
24.31+15.999 =
MgO
%O
%Mg
Formula Weight
Formula of Oxide Mg
x
O
y
Mg = 60.3%
and
O = 39.7%