For the reaction $4FeCr_2O_4 + 8Na_2CO_3 + 7O_2 \rightarrow 8Na_2CrO_4 + 2Fe_2O_3 + 8CO_2$,what is the stoichiometric ratio of the reactants $(FeCr_2O_4 : Na_2CO_3 : O_2)$?

What will be the volume of oxygen gas produced if the reaction $2 KClO_{3(s)} \longrightarrow 2 KCl_{(s)} + 3 O_{2(g)}$,$\Delta H^{\circ} = -78 \ kJ$ is carried out at $S.T.P.$ (in $L$)?

Find the mass of sodium carbonate in grams required to prepare $100 \text{ ml}$ of a $0.1 \text{ M}$ aqueous solution. (Molar mass of $Na_2CO_3 = 106 \text{ g/mol}$) (in $\text{ g}$)

If combustion of $4 \ g$ of $CH_4$ liberates $2.5 \ kcal$ of heat,the heat of combustion of $CH_4$ is ..... $kcal/mol$.

An unknown chlorohydrocarbon has $3.55\%$ of chlorine. If each molecule of the hydrocarbon has one chlorine atom only,the number of chlorine atoms present in $1\,g$ of chlorohydrocarbon is (Atomic wt. of $Cl = 35.5\,u$; Avogadro constant $= 6.023 \times 10^{23}\,mol^{-1}$)

$250 \ mL$ of a sodium carbonate solution contains $2.65 \ g$ of $Na_2CO_3$. If $10 \ mL$ of this solution is diluted to $1 \ L$, what is the concentration of the resultant solution (in $M$)?