The number of moles of hydrogen molecules required to produce 20 moles of ammonia through Haber’s process is:

A sample of magnesium carbonate weighing 30.0 g is heated until it completely decomposes to magnesium oxide and carbon dioxide. If 12.0 g of magnesium oxide is produced, what is the percentage purity of the original magnesium carbonate sample? (Atomic weight: $Mg = 24$)

The number of moles of hydrogen molecules required to produce 20 moles of ammonia through Haber’s process is:

Number of moles of $N{a_2}S{O_4}$ produced from 1 mole of NaOH

$26\,{\rm{mL}}$ of ${\rm{C}}{{\rm{O}}_2}$ are passed over hot coke. The maximum volume of CO formed is :

Two elements P and Q react to form compounds with formulas $PQ_2$ and $P_2Q$. If 0.1 mole of $PQ_2$ weighs 5 g and 0.2 mole of $P_2Q$ weighs 14 g, what are the atomic masses of P and Q?

Which sample contains the largest number of helium atoms?

Which of the following contains the largest number of water molecules?

If 50.0 g of an impure sample of limestone (calcium carbonate) is heated, it decomposes to produce 14.0 g of calcium oxide and carbon dioxide. Determine the percentage of calcium carbonate in the limestone sample. (Atomic weight: $Ca = 40$)

If $4.6$ g of formic acid and $9.0$ g of oxalic acid react with concentrated $H_2SO_4$, and the resulting gaseous mixture is passed through $KOH$ pellets, what mass of gas (in grams) will remain at STP?

25.0 g of a calcium carbonate sample decomposes on heating to give carbon dioxide and 10.0 g calcium oxide. What will be the percentage purity of calcium carbonate in the sample? (Atomic weight: $Ca = 40$)