Understanding the Problem

* Aluminum sulfide: The formula for aluminum sulfide is Al₂S₃. This means each formula unit contains 3 sulfide ions (S²⁻).

* Molarity: A 0.030 molar solution means there are 0.030 moles of aluminum sulfide dissolved in every liter of solution.

Steps to Solve

1. Moles of Aluminum Sulfide:

* Calculate the moles of aluminum sulfide in the 0.20 L solution:

0.20 L * 0.030 mol/L = 0.006 moles Al₂S₃

2. Moles of Sulfide Ions:

* Since each mole of Al₂S₃ contains 3 moles of sulfide ions, multiply the moles of Al₂S₃ by 3:

0.006 moles Al₂S₃ * 3 moles S²⁻/mole Al₂S₃ = 0.018 moles S²⁻

Answer: There are 0.018 moles of sulfate ions in the solution.

Important Note: The problem states "aluminum sulfide and oxygen." Oxygen (O₂) is not involved in the formation of sulfate ions (SO₄²⁻). This problem likely intended to focus on the sulfide ions from the aluminum sulfide.