An organic compound contains carbon,hydrogen,and oxygen with percentages of $38.71\%$,$9.67\%$,and $51.62\%$ respectively. Determine the empirical formula of this compound.

The chemical formula for calcium pyrophosphate is $Ca_2P_2O_7$. What is the formula for ferric pyrophosphate?

$A$ compound $X$ contains $32 \%$ of $A$,$20 \%$ of $B$,and the remaining percentage of $C$. Then,the empirical formula of $X$ is:
(Given atomic masses of $A = 64$,$B = 40$,$C = 32 \ u$)

$A$ carbohydrate with the empirical formula $CH_2O$ contains $1 \ g$ of hydrogen in $0.1 \ mol$ of the compound. Determine the molecular formula of the carbohydrate.

On analysis,a saturated hydrocarbon is found to contain $83.70\%$ carbon and $16.30\%$ hydrogen. The empirical formula will be (at. wt. of $C=12$, at. wt. of $H=1$).

One mole of one of the sodium salts listed below,having carbon content close to $14.3 \%$,produces $1 \ mole$ of carbon dioxide upon heating (atomic mass of $Na = 23, H = 1, C = 12, O = 16$). The salt is: