The molar mass of caffeine is $194$. It contains $28.9\%$ of nitrogen by mass. The number of nitrogen atoms in one molecule of caffeine is:

An organic compound contains $C = 40\%$,$H = 13.33\%$,and $N = 46.67\%$. Its empirical formula is:

$A$ substance contains $38.8\% \, C$,$16\% \, H$,and $45.2\% \, N$. What is the empirical formula of the substance?

$A$ compound contains $10^{-2} \%$ of phosphorus. If the atomic mass of phosphorus is $31$,the molecular mass of the compound having one phosphorus atom per molecule is :-

The empirical formula of a compound is $CH_2$. If the molar mass of the compound is $42 \ g/mol$,what is its molecular formula?

An organic compound gave the following results: $C = 53.3\%$,$H = 15.6\%$,$N = 31.1\%$. The molecular weight of the compound is $45$. What is the molecular formula of the compound?