6.022 * ten to power 23

1 Molecule oxygen consists of 2 atoms. 1 mole O2 = 6.02. 10

So the number of atoms: 2 x 6.02 x 10

^{23 }molecules (number of Avogadro).So the number of atoms: 2 x 6.02 x 10

^{23}There are 2 molecules in oxygen (02). APART from the Ozone molecules which is O3. This is because the UV rays smash 3 lots of 02 molecules into 2 lots of 03 molecules.

Take the atomic mass of oxygen and use this formula: # times avogadro's numbers(3.62 times 10 to the 4th power.) of what I remember from chemistry. Good luck!