Question

1. if 3.00 moles of h₂o are produced, how many moles of oxygen must be consumed?
2. if 2.5 moles of h₂o are produced, how many moles of hydrogen gas (h₂) must be used?

Explanation:

Step1: Balanced reaction for water formation

The synthesis of water follows:

$$2\text{H}_2 + \text{O}_2 ightarrow 2\text{H}_2\text{O}$$

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For Question 2:

Step2: Mole ratio of $\text{O}_2$ to $\text{H}_2\text{O}$

From the reaction, $\frac{n(\text{O}_2)}{n(\text{H}_2\text{O})} = \frac{1}{2}$

Step3: Calculate moles of $\text{O}_2$

$$n(\text{O}_2) = \frac{1}{2} \times n(\text{H}_2\text{O}) = \frac{1}{2} \times 3.00 = 1.50$$

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For Question 3:

Step2: Mole ratio of $\text{H}_2$ to $\text{H}_2\text{O}$

From the reaction, $\frac{n(\text{H}_2)}{n(\text{H}_2\text{O})} = \frac{2}{2} = 1$

Step3: Calculate moles of $\text{H}_2$

$$n(\text{H}_2) = 1 \times n(\text{H}_2\text{O}) = 1 \times 2.5 = 2.5$$

Answer:

1. 1.50 moles of $\text{O}_2$
2. 2.5 moles of $\text{H}_2$