Imhavng trouble understanding this simple chemistry mcq?

1 mol of H₂O₂ contains 2 mol of H atoms and 2 mol of O atoms.

Number of moles of H atoms = (20 mol) × 2 = 40 mol
(c) and (d) are incorrect.

Number of moles of O atoms = (20 mol) × 2 = 40 mol
(b) is incorrect.

Total number of atoms = (40 + 40) mol = 80 mol
(a) is correct.


The answer : (a) 80 mol of atoms

Mole question....

20 moles of H2O2 has....
40 mol H atoms
40 mol O atoms
80 moles of atoms of both kinds

a mole of a molecule will have as many moles of the individual elements as that molar value multiplied by the stoichiometric value of the element in the compound. In H2O2, there are 2 atoms of H for every molecule of H2O2 (and same for O). Thus, there must be 2 moles of H atoms for every mole of H2O2 molecules, and 2 moles of O atoms for every mole of H2O2. Thus, there are 4 moles of atoms for every mole of molecular H2O2. 4x20=80.