Determine the empirical formula of Kevlar,used in making bulletproof vests,which contains $70.6 \% \, C, \, 4.2 \% \, H, \, 11.8 \% \, N$ and $13.4 \% \, O$.

An organic compound contains $69 \%$ carbon and $4.8 \%$ hydrogen,the remainder being oxygen. Calculate the masses of carbon dioxide and water produced when $0.20 \ g$ of this substance is subjected to complete combustion.

$A$ hydrocarbon contains $10.5 \,g$ of carbon and $1 \,g$ of hydrogen. If $2.4 \,g$ of this hydrocarbon occupies a volume of $1 \,L$ at $1 \,atm$ pressure and $127 \,^{\circ}C$ temperature,what is the molecular formula of the hydrocarbon?

$0.5 \ g$ of an organic compound $(X)$ with $60 \%$ carbon will produce $........ \times 10^{-1} \ g$ of $CO_2$ on complete combustion.

In which of the following pairs of compounds is the ratio of $C$,$H$,and $O$ the same?

$A$ welding fuel gas contains carbon and hydrogen only. Burning a small sample of it in oxygen gives $3.38 \, g$ of carbon dioxide,$0.690 \, g$ of water,and no other products. $A$ volume of $10.0 \, L$ (measured at $STP$) of this welding gas is found to weigh $11.6 \, g$. Calculate:
$(i)$ empirical formula,
$(ii)$ molar mass of the gas,and
$(iii)$ molecular formula.