What will be the volume of $O_2$ gas at $STP$ which is obtained by thermal decomposition of $30.62 \ g$ $KClO_3$,with $80\%$ purity?

The combustion reaction of glucose is given as: (Molar mass of glucose = $180 \ g/mol$) $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O, \Delta H = -72 \ kcal$. The energy required for the production of $1.6 \ g$ of glucose is .......... $kcal$.

$5 \, L$ of a gaseous mixture of ethane and propane are burnt to produce total $11 \, L$ of $CO_2$. Volume percent of $C_2H_6$ in the initial mixture is

Equal weights of methane and oxygen are mixed in an empty container at $25\,^{\circ}C$. The fraction of the total pressure exerted by oxygen is

What quantity of oxygen is required for complete burning of $15.6 \ g$ benzene (in $g$)?

$10 \ g$ of a piece of marble $(CaCO_3)$ was put into excess of dilute $HCl$ acid. When the reaction was complete,$1120 \ mL$ of $CO_2$ was obtained at $STP$. The percentage of pure $CaCO_3$ in the marble is $............ \%$.