Question

In the reaction \( 2 \, \text{H}_2 + \text{O}_2 \to 2 \, \text{H}_2\text{O} \), if 4 moles of hydrogen react completely with oxygen, how many moles of water will be produced?

• A. \( 2 \, \text{mol} \)
• B. \( 4 \, \text{mol} \)
• C. \( 8 \, \text{mol} \)
• D. \( 1 \, \text{mol} \)

Hint:

In stoichiometry problems, always refer to the balanced equation to use the mole ratio between reactants and products.

Answer 1

The Correct Option is C

We are given the balanced chemical reaction: \[ 2 \, \text{H}_2 + \text{O}_2 \to 2 \, \text{H}_2\text{O} \] This indicates that 2 moles of hydrogen gas react with 1 mole of oxygen to produce 2 moles of water. Step 1: Use the mole ratio from the balanced equation From the balanced equation, the mole ratio of hydrogen to water is: \[ \frac{2 \, \text{mol H}_2}{2 \, \text{mol H}_2\text{O}} = 1 \] This means that for every 2 moles of hydrogen, 2 moles of water will be produced. Step 2: Calculate the moles of water produced We are given that 4 moles of hydrogen are reacting. According to the mole ratio: \[ \text{Moles of water} = 4 \, \text{mol H}_2 \times \frac{2 \, \text{mol H}_2\text{O}}{2 \, \text{mol H}_2} = 8 \, \text{mol H}_2\text{O} \] Answer: The number of moles of water produced is \( 8 \, \text{mol} \), so the correct answer is option (3).