What is meant by stoichiometry?

If isobutane and $n$-butane are present in a gas,then how much oxygen should be required for complete combustion of $10 \ kg$ of this gas? (in $kg$)

Equal masses of $H_2, O_2$ and methane have been taken in a container of volume $V$ at temperature $27 \ ^oC$ in identical conditions. The ratio of the volumes of gases $H_2 : O_2 :$ methane would be

At $400 \ K$,$1 \ mol$ of a hydrocarbon is completely burned. It produces $132 \ g$ of a gas along with $72 \ g$ of water vapour. The hydrocarbon is:

In an aqueous solution of $A_2B_3$,it undergoes complete ionization according to the reaction $A_2B_3 \rightleftharpoons 2A^{+3} + 3B^{-2}$. The concentration of $A^{+3}$ is equal to......

For the gaseous reaction $H_2 + Cl_2 \rightarrow 2HCl$,if $40 \ mL$ of hydrogen reacts with chlorine,the volume of chlorine required and the volume of $HCl$ formed are respectively: