How much amount of $Al_2O_3$ will be formed when $5.4 \ g$ of $Al$ reacts with $10 \ g$ of $O_2$? .......... $g$

$A$ mixture of $100 \ mmol$ of $Ca(OH)_2$ and $2 \ g$ of $Na_2SO_4$ was dissolved in water and the volume was made up to $100 \ mL$. The mass of $CaSO_4$ formed and the concentration of $OH^{-}$ in the resulting solution,respectively,are:
(Molar mass of $Ca(OH)_2$,$Na_2SO_4$ and $CaSO_4$ are $74$,$142$ and $136 \ g \ mol^{-1}$ respectively; $K_{sp}$ of $Ca(OH)_2$ is $5.5 \times 10^{-6}$)

At $100\,^oC$,a $1.5\,L$ vessel contains $0.4\,g$ of $O_2$ and $0.06\,g$ of $H_2$. $(a)$ What is the total pressure in the vessel? $(b)$ If the mixture reacts to form water at $100\,^oC$,which gas will remain in the vessel? What will be their partial pressures (in $,atm$)? $(R = 0.0821\, L\,atm\,mol^{-1}\,K^{-1})$.

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: $Ca = 40, P = 31, Si = 28, O = 16, H = 1$)

When $5 \ mol$ of reactant $A$ reacts with $8 \ mol$ of reactant $B$ in a closed rigid container according to the reaction:
$3A_{(g)} + 4B_{(g)} \to 2C_{(g)}$
$10^{2} \ kJ$ of heat was liberated. The $\Delta_rH$ of the given balanced reaction in $kJ/mol$ at $300 \ K$ is: $[R = 8 \ J/mol \cdot K]$

If $30 \ mL$ of $H_2$ and $20 \ mL$ of $O_2$ react to form water,what is left at the end of the reaction?