In an $80 \, g$ compound,the masses of elements are $C = 24 \, g$,$H = 4 \, g$,and $O = 32 \, g$. Find its empirical formula.

Insulin contains $3.4 \%$ sulfur by weight. What is its minimum molecular mass?

$A$ $1000 \ g$ sample of $NaOH$ contains $3 \ moles$ of $O$ atoms. What is the $Purity$ of $NaOH$ $\dots \dots \dots \dots \dots \dots \%$

An oxide of copper which is red in colour has the formula

At $STP$,$2.8 \, L$ of a gaseous substance weighs $5.5 \, g$. If the compound contains $N$ and $O$ atoms,its molecular formula will be ..............

The complete combustion of $0.492 \, g$ of an organic compound containing $'C'$,$'H'$,and $'O'$ gives $0.793 \, g$ of $CO_{2}$ and $0.442 \, g$ of $H_{2}O$. The percentage of oxygen composition in the organic compound is .... (nearest integer)