Question

1. Balance the following equation ___Fe(s) + ___O₂(g) ⟶ ___Fe₂O₃(s)
2. How many grams of iron (III) oxide are formed when 25 grams of iron reacts completely with oxygen?

Answers

GPT-4o mini
### 1. Balancing the Equation

To balance the reaction equation for the formation of iron(III) oxide \( \text{Fe}_2\text{O}_3 \) from iron \( \text{Fe} \) and oxygen \( \text{O}_2 \), we start with the unbalanced equation:

\[ \_\_ \text{Fe}(s) + \_\_ \text{O}_2(g) \rightarrow \_\_ \text{Fe}_2\text{O}_3(s) \]

1. **Count the number of atoms for each element in the products:**
- In \( \text{Fe}_2\text{O}_3 \), there are 2 Fe atoms and 3 O atoms.

2. **Set the coefficients for products:**
- Put a coefficient of 1 in front of \( \text{Fe}_2\text{O}_3 \):
\[ \_\_ \text{Fe} + \_\_ \text{O}_2 \rightarrow 1 \text{Fe}_2\text{O}_3 \]

3. **Adjust the coefficient for Fe to balance iron:**
- Since there are 2 Fe in the product, change Fe to 4:
\[ 4 \text{Fe} + \_\_ \text{O}_2 \rightarrow 2 \text{Fe}_2\text{O}_3 \]

4. **Adjust the coefficient for O:**
- To balance the oxygen, since there are 6 O (3 O in \( \text{Fe}_2\text{O}_3 \) times 2) in the products, you need 3 \( \text{O}_2 \):
\[ 4 \text{Fe} + 3 \text{O}_2 \rightarrow 2 \text{Fe}_2\text{O}_3 \]

So the balanced equation is:

\[ 4 \text{Fe}(s) + 3 \text{O}_2(g) \rightarrow 2 \text{Fe}_2\text{O}_3(s) \]

### 2. Calculating Grams of Iron(III) Oxide Formed

To find how many grams of iron(III) oxide \( \text{Fe}_2\text{O}_3 \) are formed from 25 grams of iron \( \text{Fe} \):

1. **Find the molar mass of Fe:**
- Iron (Fe) has a molar mass of approximately 55.85 g/mol.

2. **Convert grams of Fe to moles:**
\[
\text{moles of Fe} = \frac{25 \text{ g}}{55.85 \text{ g/mol}} \approx 0.447 \text{ moles Fe}
\]

3. **Use the balanced equation to find moles of \( \text{Fe}_2\text{O}_3 \):**
- From the balanced equation \( 4 \text{Fe} + 3 \text{O}_2 \rightarrow 2 \text{Fe}_2\text{O}_3 \), we see that 4 moles of Fe produce 2 moles of \( \text{Fe}_2\text{O}_3 \).

Therefore, the ratio of Fe to \( \text{Fe}_2\text{O}_3 \) is \( \frac{2 \text{ moles } \text{Fe}_2\text{O}_3}{4 \text{ moles Fe}} = \frac{1}{2} \):

\[
\text{moles of } \text{Fe}_2\text{O}_3 = \frac{0.447 \text{ moles Fe}}{2} \approx 0.224 \text{ moles } \text{Fe}_2\text{O}_3
\]

4. **Find the molar mass of \( \text{Fe}_2\text{O}_3 \):**
- Molar mass \( \text{Fe}_2\text{O}_3 = 2(55.85 \text{ g/mol}) + 3(16.00 \text{ g/mol}) = 159.7 \text{ g/mol} \)

5. **Convert moles of \( \text{Fe}_2\text{O}_3 \) to grams:**
\[
\text{grams of } \text{Fe}_2\text{O}_3 = 0.224 \text{ moles} \times 159.7 \text{ g/mol} \approx 35.70 \text{ g}
\]

### Final Answer:
- The balanced equation is:
\[ 4 \text{Fe}(s) + 3 \text{O}_2(g) \rightarrow 2 \text{Fe}_2\text{O}_3(s) \]
- The amount of iron(III) oxide formed from 25 grams of iron is approximately **35.70 grams**.