How many sulfur atoms are there in 21.0 g of Al₂S₃?

Question

Quizplus · Accepted Answer

To solve this problem, we need to use the molar mass of aluminum sulfide (Al2S3) and the given mass of the compound to calculate the number of moles of Al2S3 present. Then, we can use the ratio of sulfur atoms to Al2S3 molecules to calculate the number of sulfur atoms present.

First, let's calculate the molar mass of Al2S3:
2(27.0 g/mol of Al) + 3(32.1 g/mol of S) = 150.2 g/mol of Al2S3

Next, we can convert the given mass of Al2S3 to moles:
21.0 g Al2S3 x (1 mol Al2S3/150.2 g) = 0.140 mol Al2S3

Finally, we can use the ratio of sulfur atoms to Al2S3 molecules to calculate the number of sulfur atoms:
0.140 mol Al2S3 x (3 mol S/1 mol Al2S3) x (6.022 x 10^23 atoms/mole) = 2.53 x 10^23 S atoms

Therefore, the answer is B.

How Many Sulfur Atoms Are There in 21