-Calculez masa molara
1g..........0,7466l
M.............22,4l
M=30g/mol
-deduc raportul molar
40/12: 53,3/16:6,6/1= 3,33: 3,33: 6,66
nC:nO;nH=1:1:2---> formula bruta (COH2)n
- din egalitatea : n,mol(12gC+16gO+2gH)/mol=30g/mol---.> n=1
formula moleculara este CH2O