1. Balanced Chemical Equation:

The Haber process reaction is:

N₂ (g) + 3H₂ (g) ⇌ 2NH₃ (g)

This tells us that 3 moles of hydrogen gas (H₂) react to produce 2 moles of ammonia (NH₃).

2. Mole Ratio:

The mole ratio between hydrogen and ammonia is 3:2. This means for every 2 moles of ammonia produced, 3 moles of hydrogen are consumed.

3. Assuming Ideal Gas Behavior:

We can use the ideal gas law to relate moles and volume. Since we're dealing with gases at constant temperature and pressure, we can assume that the volume is directly proportional to the number of moles.

4. Calculation:

* Since we have 16 L of ammonia, we need to find out how many liters of hydrogen are needed to produce that amount.

* Using the mole ratio, we know that 3 moles of hydrogen are needed for every 2 moles of ammonia. This translates to a volume ratio of 3:2.

* To find the volume of hydrogen, we can set up a proportion:

(3 L H₂) / (2 L NH₃) = (x L H₂) / (16 L NH₃)

* Solving for x (the volume of hydrogen):

x = (3 L H₂ * 16 L NH₃) / (2 L NH₃) = 24 L H₂

Answer: 24 liters of hydrogen gas were used to produce 16 liters of ammonia.