determine the empirical formula of a compound containing 2.16 g of aluminium, 3.85 g of sulfur, and 7.68 g of oxygen

Empirical formula is Al₂S₃O₁₂.

Explanation:

Mass of aluminium = 2.16 g

Mass of sulfur = 3.85 g

Mass of oxygen = 7.68 g

Empirical formula = ?

Solution:

Number of gram atoms of Al = 2.16/27 = 0.08

Number of gram atoms of S = 3.85 / 32 = 0.12

Number of gram atoms of O = 7.68 / 16 = 0.48

Atomic ratio:

Al : S : O

0.08/0.08 : 0.12/0.08 : 0.48/0.08

1 : 1.5 : 6

Al : S : O = 2 (1: 1.5 : 6)

Al : S : O = 2 : 3 : 12

Empirical formula is Al₂S₃O₁₂.