In the reaction 2 H2(g) + O2(g) → 2 H2O(g), how many liters of H2 gas at STP are required to produce 2 moles of H2O?

• A. 11.2 L
• B. 44.8 L
• C. 2.0 L
• D. 22.4 L

Answer: (B)

Verified step by step guidance

1. Identify the balanced chemical equation: \$2 \mathrm{H}_2(g) + \mathrm{O}_2(g) \rightarrow 2 \mathrm{H}_2\mathrm{O}(g)$.
2. Determine the mole ratio between \(\mathrm{H}_2\) and \(\mathrm{H}_2\mathrm{O}\) from the balanced equation. For every 2 moles of \(\mathrm{H}_2\) consumed, 2 moles of \(\mathrm{H}_2\mathrm{O}\) are produced, so the ratio is 1:1.
3. Since you want to produce 2 moles of \(\mathrm{H}_2\mathrm{O}\), calculate the moles of \(\mathrm{H}_2\) required using the mole ratio: moles of \(\mathrm{H}_2 = 2\) moles.
4. Recall that at STP (Standard Temperature and Pressure), 1 mole of any ideal gas occupies 22.4 liters. Use this to convert moles of \(\mathrm{H}_2\) to volume: \(\mathrm{Volume} = \mathrm{moles} \times 22.4 \mathrm{L/mol}\).
5. Multiply the moles of \(\mathrm{H}_2\) by 22.4 L/mol to find the volume of \(\mathrm{H}_2\) gas required at STP to produce 2 moles of \(\mathrm{H}_2\mathrm{O}\).