Upon heating, 15.0 g of impure zinc carbonate decomposes completely to produce zinc oxide and carbon dioxide. If 5.6 g of zinc oxide is formed, calculate the percentage purity of the zinc carbonate sample. (Atomic weight: $Zn = 65.4$)

If Avogadro's number were $6.022 imes 10^{15} \, mol^{-1}$, what would be the mass of one mole of water (H$_2$O)? (Atomic masses: H = 1 u, O = 16 u)

A gaseous mixture contains oxygen and nitrogen in the ratio of $1:4$ by weight. Therefore, the ratio of their number of molecules is:

If you have 18g of water and 18g of oxygen, which contains a greater number of molecules?

The production of 10 moles of ammonia by the Haber process requires how many moles of hydrogen gas, assuming complete reaction?

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: $Ca = 40$)

If 100 mL of a 17.0% $\AgNO_3$ solution is reacted with excess NaCl, what mass of AgCl will precipitate?

Upon heating, 15.0 g of impure zinc carbonate decomposes completely to produce zinc oxide and carbon dioxide. If 5.6 g of zinc oxide is formed, calculate the percentage purity of the zinc carbonate sample. (Atomic weight: $Zn = 65.4$)

10g of which of the following substances contains the greatest number of atoms?

Which of the following contains the greatest number of helium atoms?

The relation between molecular weight $\left( M \right)$ and vapour density $\left( VD \right)$ is: