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]\( 4 Fe + 3 O_2 \rightarrow 2 Fe_2O_3 \)[/tex]
B. [tex]\( 3 Fe + 4 O_2 \rightarrow 2 Fe_2O_3 \)[/tex]
C. [tex]\( 2 Fe + 4 O_2 \rightarrow 3 Fe_2O_3 \)[/tex]
D. [tex]\( 3 Fe + 3 O_2 \rightarrow 4 Fe_2O_3 \)[/tex]
E. [tex]\( 4 Fe + 4 O_2 \rightarrow 3 Fe_2O_3 \)[/tex]



Answer :

To balance the given chemical equation [tex]\( Fe + O_2 \rightarrow Fe_2O_3 \)[/tex], we need to make sure that the number of atoms for each element is the same on both sides of the equation.

1. Initially, write down the unbalanced equation:
[tex]\[ Fe + O_2 \rightarrow Fe_2O_3 \][/tex]

2. Determine the number of atoms of each type on both sides of the equation:
- On the left: 1 Fe, 2 O
- On the right: 2 Fe, 3 O

3. To balance the number of iron (Fe) atoms, note that we need 2 Fe atoms on the left to balance the 2 Fe atoms in [tex]\( Fe_2O_3 \)[/tex]:
[tex]\[ 2 Fe + O_2 \rightarrow Fe_2O_3 \][/tex]

4. Now, we have:
- On the left: 2 Fe, 2 O
- On the right: 2 Fe, 3 O

5. To balance the oxygen atoms, observe that we have 3 oxygen atoms on the right. We need a multiple of [tex]\( O_2 \)[/tex] on the left to get 3 oxygen atoms. As [tex]\[ O_2 \][/tex] contains 2 oxygen atoms, multiplying [tex]\[ O_2 \][/tex] by 1.5 gives us 3 oxygen atoms:
[tex]\[ 2 Fe + 1.5 O_2 \rightarrow Fe_2O_3 \][/tex]

6. Since chemical equations cannot have fractional coefficients, we multiply all coefficients by 2 to eliminate the fractional coefficient:
[tex]\[ 4 Fe + 3 O_2 \rightarrow 2 Fe_2O_3 \][/tex]

Now we have a balanced equation. Let's confirm:

- On the left: 4 Fe, 6 O
- On the right: 4 Fe, 6 O

Both sides have the same number of atoms for each element.

The correct balanced equation is:
[tex]\[ 4 Fe + 3 O_2 \rightarrow 2 Fe_2O_3 \][/tex]

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