When 3.00 moles of hydrogen molecules and 1.50 moles of oxygen molecules react, they form 3.00 moles of water according to the reaction below.

How many grams of hydrogen were required to form 3.00 moles of water?

[tex]2 H_2 + O_2 \rightarrow 2 H_2O[/tex]

A. 0.0469 g
B. 1.49 g
C. 6.05 g
D. 0.672 g



Answer :

Certainly! Let's break down the problem step by step to determine how many grams of hydrogen are required to form 3.00 moles of water, based on the given chemical reaction:

[tex]\[ 2 \ H_2 + O_2 \rightarrow 2 \ H_2O \][/tex]

### Step 1: Understanding the Stoichiometry
In the balanced chemical equation provided, 2 moles of hydrogen gas ([tex]\( H_2 \)[/tex]) react with 1 mole of oxygen gas ([tex]\( O_2 \)[/tex]) to form 2 moles of water ([tex]\( H_2O \)[/tex]).

### Step 2: Mole Ratio
From the equation, we see that the mole ratio of hydrogen to water is 1:1. This means that for every 1 mole of [tex]\( H_2O \)[/tex] formed, we need exactly 1 mole of [tex]\( H_2 \)[/tex].

### Step 3: Calculate the Moles of Hydrogen Needed
Since we are forming 3.00 moles of water, we need an equal amount of hydrogen in moles due to the 1:1 ratio. Therefore, we need 3.00 moles of hydrogen.

### Step 4: Find the Molar Mass of Hydrogen
The molar mass of hydrogen ([tex]\( H_2 \)[/tex]) is 2 grams per mole. This information is crucial because it allows us to convert the moles of hydrogen to grams.

### Step 5: Calculate the Mass of Hydrogen Needed
Using the molar mass, we convert the moles of hydrogen to grams:

[tex]\[ \text{Mass of Hydrogen} = \text{Moles of Hydrogen} \times \text{Molar Mass of Hydrogen} \][/tex]

Substituting in the values, we get:

[tex]\[ \text{Mass of Hydrogen} = 3.00 \ \text{moles} \times 2 \ \text{grams/mole} \][/tex]

[tex]\[ \text{Mass of Hydrogen} = 6.00 \ \text{grams} \][/tex]

### Conclusion
Therefore, to form 3.00 moles of water, we require 6.00 grams of hydrogen. Among the given options, the closest value is:

6.05 g

So, the correct answer is:
[tex]\[ \boxed{6.05 \ g} \][/tex]