Question: how many molecules are there in 1 gram of chlorine?
Answer: 39.2 g Cl2(1 mole of Cl270.9 g Cl2)(6.022⋅1023molecules Cl21 mole Cl2)=3.33⋅1023 molecules Cl2 . Hence, 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.