What is the value of percent atom economy if the formula weight of the product is $46 \ u$ and the sum of the formula weight of all reactants is $92 \ u$ (in $\%$)?

How many litres of oxygen (at $STP$) are required for complete combustion of $39 \ g$ of liquid benzene?
(Atomic weights: $C=12, O=16, H=1$)

What volume in liters is required to prepare a $0.1 \ N$ $HNO_3$ solution from $6.3 \ g$ of $HNO_3$?

For the reaction $Fe_{2}O_{3} + 3 CO \longrightarrow 2 Fe + 3 CO_{2}$,the volume of carbon monoxide required to reduce one mole of ferric oxide is (in $dm^{3}$)

The density of a monobasic strong acid (Molar mass $24.2 \ g \ mol^{-1}$) is $1.21 \ kg \ L^{-1}$. The volume of its solution required for the complete neutralization of $25 \ mL$ of $0.24 \ M \ NaOH$ is $.............. \times 10^{-2} \ mL$ (Nearest integer).

If $1.5 \, mol$ of oxygen reacts with $Al$ to form $Al_2O_3$,calculate the mass of aluminum used in the reaction in grams.