When excess $CO_2$ is passed through a solution containing $0.205 \ mol$ of $BaCO_3$,what is the mass of $Ba(HCO_3)_2$ formed in grams?

$8 \ g$ of $H_2$ and $256 \ g$ of $HI$ are in a $4 \ L$ flask. Calculate their active mass. $(H = 1 \ g \ mol^{-1}, I = 127 \ g \ mol^{-1})$

$2 \ g$ of aluminium is treated separately with excess of dilute $H_{2}SO_{4}$ and excess of $NaOH$. The ratio of the volumes of hydrogen evolved is

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

$510 \ mg$ of a liquid on vaporisation in Victor Mayer's apparatus displaces $510 \ cm^3$ of dry air (at $NTP$). The molecular weight of the liquid is:

Based on the equation $C_6H_{6(l)} + \frac{15}{2} O_{2(g)} \rightarrow 6CO_{2(g)} + 3H_2O_{(l)}$,the enthalpy change is $\Delta H = -3264.4 \, kJ \, mol^{-1}$. How much energy in $kJ$ is released when $7.8 \, g$ of benzene is burned in air?