What will be the weight of lime $(CaO)$ obtained by heating $300 \ kg$ of $90\%$ pure limestone $(CaCO_3)$?

$10 \ mL$ of an aqueous solution containing $222 \ mg$ of calcium chloride $(mol. wt. = 111)$ is diluted to $100 \ mL$. The concentration of chloride ion in the resulting solution is $..... \ mol/L$.

$A$ mixture of $CaCl_{2}$ and $NaCl$ weighing $4.44 \ g$ is treated with sodium carbonate solution to precipitate all the $Ca^{2+}$ ions as calcium carbonate. The calcium carbonate so obtained is heated strongly to get $0.56 \ g$ of $CaO$. The percentage of $NaCl$ in the mixture (atomic mass of $Ca=40$) is

What is the normality of a $1 \, M$ solution of $H_3PO_4$?

When $26 \ mL$ of $CO_2$ is passed over hot coke,the volume of $CO$ produced is .......... $mL$.

The heat of combustion of methane is given by the following equation. How many grams of methane are required to produce $445 \ kJ$ of heat (in $g$)?
$CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O \ (\Delta H = -891 \ kJ/mol)$