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:

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

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: $Ca = 40$)

Volume occupied by $3.01 imes {10^{23}}\;\;$ molecules of acetylene at NTP is:

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

Which of the following contains the greatest number of atoms?

The volume of ammonia obtained by the complete combination of $10\,\,{\rm{mL}}$ of ${{\rm{N}}_2}$ and $30\,\,{\rm{mL}}$ of ${{\rm{H}}_2}$ is:

1 mol of $C{H_4}$ contains

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: $Ca = 40$)

Which sample contains the largest number of helium atoms?

The mass of 2.5 g.atom of oxygen is