What is the approximate mass of the precipitate formed when $50 \text{ mL}$ of $16.9\%$ solution of $AgNO_3$ is mixed with $50 \text{ mL}$ of $7.45\%$ $KCl$ solution (in $\text{ g}$)? (Molar mass of $AgNO_3 = 169 \text{ g/mol}$, $KCl = 74.5 \text{ g/mol}$, $AgCl = 143.3 \text{ g/mol}$)

Phosphoric acid is prepared commercially from phosphate ore as follows:
$Ca_3(PO_4)_2 + 3SiO_2 + 5C + 5O_2 + 3H_2O \to 3CaSiO_3 + 5CO_2 + 2H_3PO_4$
If $1.0 \ kg$ each of calcium phosphate and silica are used with an excess of $C$,$O_2$,and $H_2O$,what is the maximum quantity of phosphoric acid that can be produced (in $kg$)? (Atomic masses: $Ca = 40, P = 31, Si = 28, O = 16, H = 1$)

In the reaction $2H_2 + O_2 \to 2H_2O$,if $6 \ g$ of $H_2$ combines with $64 \ g$ of $O_2$,find the mass of the excess reagent left in $g$.

$3O_2 + 2N_2 \to 2N_2O_3$
$9 \ mol$ of $O_2$ and $14 \ mol$ of $N_2$ are allowed to react. When $3 \ mol$ of $O_2$ remains unreacted,how many moles of $N_2O_3$ would have been produced?

$20$ moles of $A$ and $14$ moles of $B$ are mixed and allowed to react according to the equation $A + 2B \rightarrow 3C$. What is the maximum number of moles of $C$ which could be prepared?

If $0.5 \ mol$ of $BaCl_2$ is mixed with $0.1 \ mol$ of $Na_3PO_4$,what is the maximum number of moles of $Ba_3(PO_4)_2$ formed?