Question

Which of the following samples contains the smallest number of molecules?
A. 1g of phosphorus, P4
B. 1g of chlorine, Cl2
C. 1g of nitrogen, N2
D. 1g of sulfur, S8

Answer 1

Here is what you do. I'll use Cl2 as an example.
mols Cl2 = grams/molar mass = 1/71 = ? whatever.
Then you know 1 mol Cl2 contains 6.02E23 x whatever above = number of molecules.
Now you do the same for P4, N2, and S8 along with completing Cl2, then compare to which number of molecules is the smallest.