$A$ compound contains $2.8\%$ $Fe$ by mass. If the compound contains a single $Fe$ atom in its one molecule,then the molar mass $(g/mol)$ of the compound is $(Fe = 56\, amu)$.

On combustion,$0.210 \ g$ of an organic compound containing $C$,$H$,and $O$ gave $0.127 \ g$ $H_2O$ and $0.307 \ g$ $CO_2$. The percentages of hydrogen and oxygen in the given organic compound respectively are $:$

In a compound,$C, H,$ and $N$ are present in the weight ratio of $9:1:3.5$. If its molecular weight is $108$,then its molecular formula will be:

Hemoglobin contains $0.334 \% \, Fe$ by weight. If the molecular mass of hemoglobin is approximately $67200 \, g/mol$,determine the number of iron atoms in one molecule of hemoglobin. (Atomic mass of $Fe = 56 \, g/mol$)

In an organic compound,the percentage of $C$ is $92.3 \%$. What is its empirical formula?

Complete combustion of $1.80 \, g$ of an oxygen-containing compound $(C_xH_yO_z)$ gave $2.64 \, g$ of $CO_2$ and $1.08 \, g$ of $H_2O$. The percentage of oxygen in the organic compound is