1. Write the Balanced Chemical Equation:

The reaction between dihydrogen sulfide (H₂S) and oxygen (O₂) produces sulfur dioxide (SO₂) and water (H₂O). The balanced equation is:

2 H₂S + 3 O₂ → 2 SO₂ + 2 H₂O

2. Determine the Mole Ratio:

From the balanced equation, we see that 2 moles of H₂S react with 3 moles of O₂.

3. Convert Grams of H₂S to Moles:

* Find the molar mass of H₂S: 1.01 g/mol (H) * 2 + 32.07 g/mol (S) = 34.09 g/mol

* Convert 2.5 g of H₂S to moles: 2.5 g / 34.09 g/mol = 0.0733 mol H₂S

4. Calculate Moles of O₂ Needed:

* Use the mole ratio from the balanced equation: (0.0733 mol H₂S) * (3 mol O₂ / 2 mol H₂S) = 0.110 mol O₂

5. Convert Moles of O₂ to Grams:

* Find the molar mass of O₂: 16.00 g/mol (O) * 2 = 32.00 g/mol

* Convert 0.110 mol O₂ to grams: 0.110 mol * 32.00 g/mol = 3.52 g O₂

Therefore, you need 3.52 grams of oxygen to react with 2.5 grams of dihydrogen sulfide.