The maximum number of moles of $CaSO_4$ produced by the reaction of $0.5 \ mol$ of $H_2SO_4$ with $0.2 \ mol$ of $Ca(OH)_2$ is ........

$20$ 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?

In the reaction $4NH_{3(g)} + 5O_{2(g)} \rightarrow 4NO_{(g)} + 6H_2O_{(g)}$,when $1 \ mol$ of ammonia and $1 \ mol$ of $O_2$ react to completion:

In Ostwald's process for the manufacture of nitric acid,the first step involves the oxidation of ammonia gas by oxygen gas to give nitric oxide gas and steam. What is the maximum weight of nitric oxide that can be obtained starting only with $10.00 \ g$ of ammonia and $20.00 \ g$ of oxygen?

$2 SO_{2(g)} + O_{2(g)} \rightarrow 2 SO_{3(g)}$
The above reaction is carried out in a vessel starting with partial pressures $P_{SO_{2}} = 250 \ mbar$,$P_{O_{2}} = 750 \ mbar$,and $P_{SO_{3}} = 0 \ mbar$. When the reaction is complete,the total pressure in the reaction vessel is $..... \ mbar$. (Round off to the nearest integer).

What are $x$ and $y$ in the following reaction?
$x Pb_3O_4 \rightarrow y PbO + O_2$