What would be the mass of 6.022 x 10^23 argon atoms?

39.948g Ar, or if you need to round it up then 39.95g

Explanation:

Conversion units: 1 mole is 6.022 x 10^23 molecules, that includes atoms too.

First Step: Convert atoms to moles:

6.022 x 10^23 Ar atoms × = 1 mole Ar

Second Step: Convert moles to grams

There is 39.948 grams in one mole of Argon so

1 mole Ar x 39.948g = 39.948g