Answer:
1 mole of SO2 = 1 mole of S + 2 moles of O
It is a well-known fact that
1 mole of any substance contains 6.023x10^23 particles.
So,
1 mole of O = 6.023x10^23 atoms
As there are 2 moles of Oxygen in SO2, therefore
2 moles of O = 2 x 6.023x10^23 atoms
2 moles of O = 12.046x10^23 atoms
Now it is obvious that
12.046x10^23 atoms of Oxygen are present in 1 mole of SO2.
Explanation: