The numbers of moles of BaCO3 which contains 1.5 moles of oxygen atoms is
In formula of BaCO3 there are 3 atoms of oxygen.Therefore one mole of BaCO3 contain 3 moles of Oxygen atom.
OR, 3 moles of Oxygen atom = 1 mole of BaCO3
therefore 1.5 moles of Oxygen atom = 1/3 *1.5 = 0.5 moles of BaCO3
OR, 3 moles of Oxygen atom = 1 mole of BaCO3
therefore 1.5 moles of Oxygen atom = 1/3 *1.5 = 0.5 moles of BaCO3