Question

How many atoms of Oxygen are in 1.4 moles of NO₂

Answer 1

Molecular formula is NO₂

That is 1 mole of NO₂ contains 2 moles of Oxygen atoms.

So, 1.4 moles of NO₂ would contain 1.4 mol * 2 /1 = 2.8 mol of Oxygen atoms

Number of moles of Oxygen atoms = 2.8 moles

We know that

1 mole of any substance contains Avogadro’s number (6.022 × 10²³) of atoms / molecules / ions.

That is

1 mole of Oxygen atoms contain Avogadro’s number (6.022 × 10²³) of atoms.

So, 2.8 moles of Oxygen contains 2.8 mol * 6.022 × 10²³ atoms / 1 mol = 1.68616 × 10²⁴ atoms

Number of Oxygen atoms = 1.69 × 10²⁴ Oxygen atoms