Calculate the mass of iron which will be converted into its oxide (`Fe_3O_4`) by the action of 35g of steam on it. [At mass of Fe=56] `Fe+H_2​O→Fe_3O_4+4H_2` ​

Options

A. 80g
B. 82g
C. 26g
D. 68g

Explanation

To solve the problem of calculating the mass of iron that will be converted into its oxide (Fe₃O₄) by the action of 35g of steam, we can follow these steps:

### Step 1: Write the balanced chemical equation
The reaction given is:
\[ \text{Fe} + \text{H}_2\text{O} \rightarrow \text{Fe}_3\text{O}_4 + 4\text{H}_2 \]

### Step 2: Balance the equation
The balanced equation is:
\[ 3\text{Fe} + 4\text{H}_2\text{O} \rightarrow \text{Fe}_3\text{O}_4 + 4\text{H}_2 \]

### Step 3: Calculate the molar mass of Fe₃O₄
- The molar mass of iron (Fe) = 56 g/mol
- Molar mass of Fe₃O₄ = \( 3 \times 56 + 4 \times 16 = 168 + 64 = 232 \) g/mol

### Step 4: Calculate the mass of water (H₂O)
- The molar mass of water (H₂O) = \( 2 \times 1 + 16 = 18 \) g/mol

### Step 5: Determine the mass ratio from the balanced equation
From the balanced equation:
- 3 moles of Fe react with 4 moles of H₂O.
- Mass of 3 moles of Fe = \( 3 \times 56 = 168 \) g
- Mass of 4 moles of H₂O = \( 4 \times 18 = 72 \) g

### Step 6: Set up a proportion to find the mass of Fe for 35 g of H₂O
Using the ratio from the balanced equation:
\[ \frac{168 \text{ g Fe}}{72 \text{ g H}_2\text{O}} = \frac{x \text{ g Fe}}{35 \text{ g H}_2\text{O}} \]

### Step 7: Solve for x (mass of Fe)
Cross-multiplying gives:
\[ 168 \times 35 = 72 \times x \]
\[ 5880 = 72x \]
\[ x = \frac{5880}{72} \approx 81.67 \text{ g} \]

### Step 8: Round the answer
The mass of iron that will be converted into its oxide is approximately 82 g.

### Final Answer
The mass of iron converted into its oxide by the action of 35g of steam is approximately **82 g**.

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