The minimum number of moles of $O_2$ required for complete combustion of $1$ mole of propane and $2$ moles of butane is...

What is the stoichiometric ratio of the products in the reaction: $3K_2MnO_4 + 2H_2SO_4 \rightarrow 2KMnO_4 + 2K_2SO_4 + MnO_2 + 2H_2O$?

What is $\Delta n$ for the combustion of $1 \ mole$ of benzene,when both the reactants and the products are in the gaseous state at $298 \ K$?

$x$ grams of calcium carbonate was completely burnt in air. The weight of the solid residue formed is $28 \,g$. What is the value of $x$ (in grams)?

If the density of iron is $7.86 \, g \, cm^{-3}$ and its atomic mass is $55.85 \, u$,then find the volume occupied by $1 \, mol$ of iron atoms in $cm^{3}$.

Calculate the number of $Cl^{-}$ ions in $222 \ g$ anhydrous calcium chloride? (At. mass $Ca=40, Cl=35.5$)