An organic compound contains $C = 36\%$,$H = 6\%$ and the rest is oxygen. Its empirical formula is:

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:

$60 \ g$ of a compound on analysis gave $C = 24 \ g$,$H = 4 \ g$ and $O = 32 \ g$. Its empirical formula is

Hemoglobin contains $0.34 \%$ of iron by mass. The number of $Fe$ atoms in $3.3 \ g$ of hemoglobin is. (Given : Atomic mass of $Fe$ is $56 \ u, N_A = 6.022 \times 10^{23} \ mol^{-1}$)

An organic compound contains $C$,$H$ and $S$. The minimum molecular weight of the compound containing $8\%$ sulphur is........$g\,mol^{-1}$ (atomic weight of $S = 32\,amu$)

The percentage of nitrogen by mass in ammonium sulphate is closest to $.....$ $\%$ (atomic masses of $H = 1, N = 14, O = 16, S = 32$ ).