Given the reaction 2 H2 + O2 → 2 H2O, if 2 moles of H2 react with excess O2, how many moles of water are produced?

Given the reaction 2 H2 + O2 → 2 H2O, if 2 moles of H2 react with excess O2, how many moles of water are produced?

• A. One
• B. Two
• C. Three
• D. Four

Answer: (B)

This question tests understanding of mole ratios from a balanced equation. The equation shows that 2 moles of hydrogen react with 2 moles of water produced, meaning the ratio of hydrogen to water is 2:2, which simplifies to 1:1. Since oxygen is in excess, hydrogen is the limiting reactant and all of it can react. Therefore, for every 2 moles of hydrogen that react, you get 2 moles of water, a direct 1-to-1 correspondence. With 2 moles of H2 available, the reaction yields 2 moles of water.

This question tests understanding of mole ratios from a balanced equation. The equation shows that 2 moles of hydrogen react with 2 moles of water produced, meaning the ratio of hydrogen to water is 2:2, which simplifies to 1:1. Since oxygen is in excess, hydrogen is the limiting reactant and all of it can react. Therefore, for every 2 moles of hydrogen that react, you get 2 moles of water, a direct 1-to-1 correspondence. With 2 moles of H2 available, the reaction yields 2 moles of water.