NEET Chemistry Some Basic Concepts in Chemistry Mole Concept MCQs

Equal masses of oxygen and ozone are present in a container at 298 K. The ratio of their partial pressures ($P_{O_2} : P_{O_3}$) is:

A compound contains 28% nitrogen and 72% of a metal by weight. Three atoms of metal combine with two atoms of nitrogen. If the atomic weight of nitrogen is 14, the atomic weight of the metal is:

Which of the following contains the greatest number of atoms?

Which of the following has the largest number of atoms?

If you have 2 g of each of the following substances, which one would contain the highest number of atoms?

Which of these samples contains the fewest atoms?

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

If you have samples of 0.5 moles of water, 36 g of water, and 3.011 x 10²³ molecules of water, which sample has the greatest mass?

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)

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: $Ca = 40$)