An unknown compound contains only C, H, and O. Combustion of 4.40 g of this compound produced 10.4 g of CO2 and 2.83 g of H2O.

Answer 1

figure the mass of carbon in 10.4g CO3
figure the mass of H2 in 2.83g H2O

so in the original molecules
CxHyOz you know the mass of Cx, how many moles is that?
you know the mass of Hy, how many moles is that?

you know now the mole ratio of C:H in the original compound.
It is not possible to find the subscript of O in the compound.