Answer:
1090 grams Sulfur (3 sig-figs)
Step-by-step explanation:
Given 2.05 x 10²⁵ molecules CaSO₄ => 2.05 x 10²⁵ Sulfur atoms (subscript = 1 mole).
Converting 2.05 x 10²⁵ sulfur atoms to moles, divide by Avogadro's Number
(= 6.023 x 10²³ sulfur atoms / mole sulfur) => 2.05 x 10²⁵ sulfur atoms/6.023 x 10²³ sulfur atoms/mole sulfur atoms = 34.036 moles sulfur atoms.
Converting 34.036 moles sulfur to grams sulfur multiply by formula wt. of sulfur (=32g/mole S)
=> 34.036moles S x 32g/mole S = 1089.158 grams S ≅ 1090 g S (3 sig-figs)