Answered

Select the correct answer.

Iron reacts with atmospheric oxygen to form iron oxide or ferric oxide. Look at the chemical equation for this reaction:

[tex]\[ Fe + O_2 \rightarrow Fe_2O_3 \][/tex]

This equation is unbalanced. Which of the following is the correct balanced equation for this reaction?

A. [tex]\[ 4Fe + 3O_2 \rightarrow 2Fe_2O_3 \][/tex]

B. [tex]\[ 3Fe + 4O_2 \rightarrow 2Fe_2O_3 \][/tex]

C. [tex]\[ 2Fe + 4O_2 \rightarrow 3Fe_2O_3 \][/tex]

D. [tex]\[ 3Fe + 3O_2 \rightarrow 4Fe_2O_3 \][/tex]

E. [tex]\[ 4Fe + 4O_2 \rightarrow 3Fe_2O_3 \][/tex]



Answer :

To determine the correct balanced equation for the reaction between iron (Fe) and atmospheric oxygen (O₂) to form iron oxide (Fe₂O₃), we need to ensure that the number of atoms for each element is the same on both the reactant and product sides of the equation. Here’s a step-by-step process to balance the equation:

1. Write the unbalanced equation:
[tex]\[ Fe + O_2 \rightarrow Fe_2O_3 \][/tex]

2. Identify the number of atoms of each element on both sides of the equation:
For the reactants:
- Iron (Fe): 1 atom
- Oxygen (O₂): 2 atoms

For the products:
- Iron (Fe): 2 atoms (in Fe₂O₃)
- Oxygen (O): 3 atoms (in Fe₂O₃)

3. Balance the iron (Fe) atoms:
To balance the iron atoms, we need 4 atoms of Fe on the reactant side, because \(2 \times Fe_2O_3\) will give us 4 Fe atoms on the product side. This can be achieved by placing a coefficient of 4 before Fe:

[tex]\[ 4 Fe + O_2 \rightarrow 2 Fe_2O_3 \][/tex]

4. Balance the oxygen (O) atoms:
Now we have 6 oxygen atoms on the product side (since \(2 \times Fe_2O_3\) results in \(2 \times 3\) O atoms). To balance the oxygen atoms, we need 6 oxygen atoms on the reactant side. Since each O₂ molecule contains 2 oxygen atoms, placing a coefficient of 3 before O₂ will give us 6 oxygen atoms:

[tex]\[ 4 Fe + 3 O_2 \rightarrow 2 Fe_2O_3 \][/tex]

5. Verify the balance:
- Reactants:
- Fe: 4 atoms
- O: \(3 \times 2 = 6\) atoms
- Products:
- Fe: \(2 \times 2 = 4\) atoms
- O: \(2 \times 3 = 6\) atoms

The equation is balanced, with 4 iron atoms and 6 oxygen atoms on both sides.

Therefore, the correct balanced equation for this reaction is:

[tex]\[ 4 Fe + 3 O_2 \rightarrow 2 Fe_2O_3 \][/tex]

Thus, the correct answer is:
A. [tex]\( 4 Fe + 3 O_2 \rightarrow 2 Fe_2O_3 \)[/tex]