an organic compound contains 66.7% C, 11.1% H and had a remainder is
oxygen. it relative formula mass was 72. find the empirical formula of the
compound and the molecular formula of the compound
 (O)  100  66.7  11.1  22.2%
C X OY H Z
X :Y : Z 
X :Y : Z 
1
:
2
:
3
M1 M 2 M 3
66.7 22.2 11.1
:
:
 5.56 : 1.39 : 11.1  4 : 1 : 8
12 16
1
12*4+1*16+8*1=72  C4H8O