Moles and Avogadro's Number Question

[s3a]

"How many atoms of chlorine are there in 48.5 grammes of elemental chlorine (Cl2)?"

Answer: 8.22*10^23 molecules (apparently)

But I get:

70.9g/1 mol = 48.5g/n

n = 0.684062059 mol

(0.684062059 mol)(6.022*10^23) = 4.12*10^23 which is half the answer. Why is this so? I put 70.9g instead of 35.45g because there are two Chlorine atoms in Cl2. What am I not thinking of in the right way?

Any help would be greatly appreciated!
Thanks in advance!

[s3a]

But the teacher's notes has 8.22*10^23 molecules as the final answer.

and when I do (0.684mol)(6.022*10^23 molecules)(2) I get 8.24*10^23

[Sodapop]

But the teacher's notes has 8.22*10^23 molecules as the final answer.

and when I do (0.684mol)(6.022*10^23 molecules)(2) I get 8.24*10^23It seems you are right:

Cl = 35.453g
Cl2 = 70.906g

48.5g / 70.906g = 0.684 moles

(0.684) x (6 x 10^23) = 4.104 x 10 ^23

There is no other way I can illustrate this being different in my head.

Are you sure you teacher is right, or did you make sure you copied the right question?

[s3a]

We don't copy down stuff, he sends us our notes and homework as pdf files :) but how do we explain the multiplication by 2?

[Sonic]

But the teacher's notes has 8.22*10^23 molecules as the final answer.

and when I do (0.684mol)(6.022*10^23 molecules)(2) I get 8.24*10^23

I also can't see anything that you've done wrong

[Sodapop]

We don't copy down stuff, he sends us our notes and homework as pdf files :) but how do we explain the multiplication by 2?There shouldn't be any multiplication by 2.

Ask your teacher about it, he or she probably made a mistake.