$1.0 \ g$ of magnesium is burnt with $0.56 \ g \ O_2$ in a closed vessel. Which reactant is left in excess and how much? (At. $wt. \ Mg = 24, O = 16$)

For the reaction $A + 2B \to C$,$5 \ mol$ of $A$ and $8 \ mol$ of $B$ will produce:

$108 \ g \ Al$ and $213 \ g \ MnO$ were heated to initiate the reaction:
$2 Al + 3 MnO \to Al_2O_3 + 3 Mn$
Which of the following is correct? (Atomic weights: $Mn = 55$,$Al = 27$)

What volume of hydrogen gas at $STP$ would be liberated by the action of $50 \text{ mL}$ of $H_2SO_4$ of $50\%$ purity (density = $1.3 \text{ g mL}^{-1}$) on $20 \text{ g}$ of zinc (in $L$)? Given: Molar mass of $H, O, S, Zn$ are $1, 16, 32, 65 \text{ g mol}^{-1}$ respectively.

Production of iron in a blast furnace follows the following equation:
$Fe_{3}O_{4(s)} + 4CO_{(g)} \rightarrow 3Fe_{(s)} + 4CO_{2(g)}$
When $4.640 \ kg$ of $Fe_{3}O_{4}$ and $2.520 \ kg$ of $CO$ are allowed to react,the amount of iron (in $g$) produced is $....$
[Given: Molar Atomic mass $(g \ mol^{-1}): Fe = 56, O = 16, C = 12$]

$A$ reaction gas mixture contains $50 \%$,$30 \%$,and $20 \%$ of $A$,$B$,and $C$ by volume,respectively. The mixture undergoes the following reactions:
$1. A + 2B \rightarrow P_1$
$2. 4P_1 + 3C \rightarrow P_2$
$P_1$ and $P_2$ are two products of the reactions. Choose the correct answer if the reaction completes.