To get the answer, you must know first the formula:
We know that moles = mass divided by molecular weight
So to get the mass, we need to alter the original formula, so
mass of sodium = 1.5 moles x atomic weight of Na
so what is the atomic weight of Sodium? It is 22.989769 u.
so the mass of sodium = 1.5 moles x 22.989769 u = 34.4846535