Answer:
0.348 moles Ar
Step-by-step explanation:
You can determine the moles of argon (Ar) by multiplying the given mass by the atomic mass of argon. This number gives the mass in grams per 1 mole. It is important to arrange the conversion in a way that allows for the cancellation of units. The final answer should have 3 significant figures to match the sig figs of the given value (13.9 = 3 sig figs).
Atomic Mass (Ar): 39.948 g/mol
13.9 g Ar 1 mole
----------------- x ------------------ = 0.348 moles Ar
39.948 g