How do I do that?

That is vague as question...

If you had 0.01 moles of Hydrogen atoms, that would be 0.01g
If you had 0.01 moles of Hydrogen molecules, that would be 0.02g

All this to tell you that the general formula for that conversion is:



where mass is in grams

For molecules and formulae like Cl2 and NaCl respectively, we use



0.01mol of Cl2 = 0.01 x (35.5 x 2) = 0.7g
0.01mol of NaCl = 0.01 x (23 + 35.5) = 0.585g

Did you understand? :)