Final answer:
To find the mass of 2.90 x 10^21 atoms of chromium, convert atoms to moles using Avogadro's number, and then multiply by the molar mass of chromium. The resulting mass is 0.2505 grams.
Step-by-step explanation:
To determine the mass in grams of 2.90 x 1021 atoms of chromium, we need to use Avogadro's number, which is 6.022 x 1023 atoms per mole, and the fact that one mole of chromium has a mass of 52.00 g. First, find how many moles of chromium atoms we have:
(2.90 x 1021 atoms) / (6.022 x 1023 atoms/mol) = 4.818 x 10-3 moles of Cr
Next, calculate the mass in grams:
4.818 x 10-3 moles of Cr x 52.00 g/mol = 0.2505 g of Cr
Therefore, 2.90 x 1021 atoms of chromium have a mass of 0.2505 grams.