1. Write the balanced chemical equation:

N₂ (g) + 3 H₂ (g) → 2 NH₃ (g)

This equation tells us that 1 mole of nitrogen gas reacts with 3 moles of hydrogen gas to produce 2 moles of ammonia.

2. Determine the moles of ammonia:

You are given 18.00 grams of ammonia (NH₃). To find the moles, use the molar mass of ammonia:

* Molar mass of NH₃ = 14.01 g/mol (N) + 3(1.01 g/mol) (H) = 17.03 g/mol

Moles of NH₃ = (18.00 g) / (17.03 g/mol) = 1.057 mol NH₃

3. Use the mole ratio from the balanced equation:

The balanced equation shows that 2 moles of NH₃ are produced for every 3 moles of H₂. Set up a proportion:

(3 mol H₂) / (2 mol NH₃) = (x mol H₂) / (1.057 mol NH₃)

4. Solve for x (moles of H₂):

Cross-multiply and solve for x:

2x = 3 * 1.057

2x = 3.171

x = 1.586 mol H₂

Therefore, you would need 1.586 moles of hydrogen gas to produce 18.00 grams of ammonia.