The flux
of oxygen molecules under these conditions is 3.58 x 10^{24}
molecules m^{-2} s^{-1
}

**Rationale**

The incident flux is given by the following equation (with all quantities expressed in SI units).

[
molecules m^{-2} s^{-1} ]

In this instance ,

P = (1/760) x 101325 = 133.3 N m^{-2}

and

m = 32 x 1.66x10^{-27} = 5.32x10^{-26}
kg

so

F = 133.3 / (2 x 3.1416 x 5.32x10^{-26} x 1.38x10^{-23}
x 300 )^{1/2}

i.e. F = 3.58 x 10^{24} molecules
m^{-2} s^{-1}