$4.0 \ g$ of a mixture containing $Na_2CO_3$ and $NaHCO_3$ is heated to $673 \ K$. The loss in mass of the mixture is found to be $0.62 \ g$. The percentage of sodium carbonate in the mixture is:

The amount of calcium oxide produced on heating $150 \ kg$ of limestone ($75 \%$ pure) is $........... \ kg$ $(Nearest \ integer)$. Given: Molar mass (in $g \ mol^{-1}$) of $Ca = 40, O = 16, C = 12$.

In the reaction $2 KClO_{3(s)} \longrightarrow 2 KCl_{(s)} + 3 O_{2(g)}$,$\Delta H^{\circ} = -78 \ kJ$. If $33.6 \ L$ of oxygen gas is liberated at $S.T.P.$,what is the mass of $KCl_{(s)}$ produced (in $g$)? (Atomic mass: $K = 39, Cl = 35.5 \ g \ mol^{-1}$)

When $CO_2$ is bubbled through $0.205 \ mol$ of $Ba(OH)_2$,how many grams of $BaCO_3$ will be produced?

When $100 \, ml$ of $0.1 \, M$ $H_2SO_4$ reacts with $Na_2CO_3$, how many liters of $CO_2$ will be produced at $STP$ (in $L$)?

Which of the following is the correct formula to determine percent atom economy?