Answer:- 30.3 g Argon.
Solution:- It asks to calculate the mass of Argon for it's 17.0 L at STP.
We know that, at STP (standard temperature and pressure), the volume of 1 mol of a gas is 22.4 L. let's calculate the moles of argon gas in it's given 17.0 L volume and multiplied it by the atomic mass of argon to get the grams. The calculations are shown as:
[tex]17.0L(\frac{1mol}{22.4L})(\frac{39.95g}{1mol})[/tex]
(where 39.95 is the atomic mass of Ar.)
= 30.3 g
So, the mass of 17.0 L of argon at STP is 30.3 g.