Question

!) Calculate the number of oxygen atoms in 0.2 mole of Na₂CO₃ . 10H₂O

Answer 1

As per the given chemical formula- Na₂CO₃.10H₂O, one mole of the chemical compound contains 13 moles of oxygen atoms. Hence

Number of moles of oxygen atoms in one mole of Na₂CO₃.10H₂O = 13

number of moles of oxygen atoms in 0.2 moles of Na₂CO₃.10H₂O = 13 X 0.2 = 2.6

Now, one mole of a substance contains 6.022 X 10²³ particles of the substance. Thus

number of atoms of oxygen in one mole of oxygen atom = 6.022 X 10²³

number of moles of oxygen atoms in 2.6 moles of oxygen atoms = 2.6 X 6.022 X 10²³ = 15.657 X 10²³

= 1.566 X 10²⁴

Thus, there are 1.566 X 10²⁴ atoms of oxygen in 0.2 moles of Na₂CO₃.10H₂O.