the answer is 3.33⋅1023 molecules of Cl2. Note that 6.022⋅1023 is also known as Avogadro's number, and it can be referred to as the number of molecules in one mole of that substance. Also, I calculated 70.9 because 35.45 g/mol (the mass of one Chlorine atom) times 2 is 70.9 g/mol (Cl2 has two Chlorine atoms).
