The molecular formula of sulphur is

The molecular mass of caffeine is $194 \, a.m.u.$. It contains $28.9 \%$ of nitrogen by mass. The number of nitrogen atoms in one molecule of caffeine is ...............

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?

If the percentage of $Se$ (atomic weight $78.4$) in a peroxidase anhydrous enzyme is $0.5\%$,what is the minimum molecular weight of the peroxidase anhydrous enzyme?

An organic compound has an empirical formula $CH_2O$,its vapour density is $45$. The molecular formula of the compound is

Calculate the amount of aluminium present in $Al_2(SO_4)_3$ if the compound contains $4 \text{ g}$ of sulfur. [Molar mass of sulfur = $32 \text{ g/mol}$, Molar mass of $Al = 27 \text{ g/mol}$] (in $\text{ g}$)