In a compound,the ratio of masses of $H, C, O,$ and $N$ is $1:3:4:7$. The empirical formula is

$A$ 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?

The percentage of $Se$ in peroxidase enzyme is $0.5\%$ by mass (atomic mass of $Se = 78.4 \ amu$). Then,the minimum molecular mass of enzyme which contains not more than one $Se$ atom is

An organic compound on analysis gave $C = 48 \,g$, $H = 8 \,g$ and $N = 56 \,g$. The volume of $1.0 \,g$ of the compound was found to be $200 \,mL$ at $NTP$. What is the molecular formula of the compound?

$0.30 \ g$ of an organic compound containing $C$,$H$ and $O$ on combustion yields $0.44 \ g \ CO_2$ and $0.18 \ g \ H_2O$. If $1 \ mol$ of the compound weighs $60 \ g$,then the molecular formula of the compound is:

Percentage of gold in $14$ carat gold is (in $\%$)