1. Understand Avogadro's Number:

* Avogadro's number states that one mole of any substance contains 6.022 x 10^23 particles (atoms, molecules, ions, etc.).

2. Set up a Conversion Factor:

* We can use Avogadro's number as a conversion factor to relate the number of molecules to moles:

(6.022 x 10^23 molecules) / (1 mole)

3. Calculate the Moles:

* Divide the given number of molecules by Avogadro's number:

(9.02 x 10^23 molecules) / (6.022 x 10^23 molecules/mole) = 1.50 moles

Therefore, 9.02 x 10^23 molecules of chlorine gas contain 1.50 moles.