Calculate the volume of $99 \text{ g}$ of $CO_2$ at $STP$. (in $\text{ L}$)

What mass of $95 \%$ pure $CaCO_3$ will be required to neutralise $50 \ mL$ of $0.5 \ M \ HCl$ solution according to the following reaction? (In $g$)
$CaCO_{3(s)} + 2HCl_{(aq)} \rightarrow CaCl_{2(aq)} + CO_{2(g)} + H_2O_{(l)}$
[Calculate up to the second decimal place]

Equal volumes of $0.1 \ M$ $AgNO_3$ and $0.2 \ M$ $NaCl$ are mixed. The concentration of $NO_3^-$ ion in the mixture will be ............ $M$.

What is the mass of potassium chloride produced when $12.25 \ g$ of potassium chlorate undergoes decomposition (in $g$)? (Atomic masses: $K=39, Cl=35.5, O=16$)

How many grams of $HCl$ will be present in $150 \ mL$ of its $0.52 \ M$ solution?

When equal volumes of $0.1 \, M \, AgNO_3$ and $0.2 \, M \, NaCl$ are mixed,the concentration of $NO_3^-$ in the resulting mixture will be .......... $M$.