1. Write the balanced chemical equation:

2 H₂ (g) + O₂ (g) → 2 H₂O (l)

This equation tells us that 2 moles of hydrogen gas (H₂) react with 1 mole of oxygen gas (O₂) to produce 2 moles of water (H₂O).

2. Determine the mole ratio:

The balanced equation shows a 2:2 mole ratio between hydrogen gas and water. This means for every 2 moles of hydrogen gas, 2 moles of water are produced.

3. Calculate the moles of water:

Since the mole ratio is 2:2, the number of moles of water produced is equal to the number of moles of hydrogen gas used:

Moles of H₂O = Moles of H₂ = 1.4 moles

Therefore, 1.4 moles of water are produced from the complete reaction of 1.4 moles of hydrogen gas.