To determine the balanced equation for the reaction where iron (Fe) reacts with oxygen (O₂) to form iron oxide (Fe₂O₃), follow these steps:
1. Write the unbalanced equation:
[tex]\[
Fe + O_2 \rightarrow Fe_2O_3
\][/tex]
2. Count the number of atoms of each element on both sides of the equation:
- Left side:
- Fe: 1
- O₂: 2 (so, O: 2)
- Right side:
- Fe: 2
- O: 3
3. Balance the number of Fe atoms:
- To balance Fe, we need 4 Fe atoms on the left because 2 Fe atoms are present in 1 molecule of Fe₂O₃. You adjust it by placing a coefficient of 4 in front of Fe on the left side of the equation:
[tex]\[
4 Fe + O_2 \rightarrow 2 Fe_2O_3
\][/tex]
- Now, count the atoms again:
- Left side:
- Fe: 4
- O₂: 2 (so, O: 2)
- Right side:
- Fe: 4 (in 2 Fe₂O₃)
- O: 6 (in 2 Fe₂O₃)
4. Balance the number of O atoms:
- To balance O, we need 3 molecules of O₂ on the left because you have 6 O atoms in 2 Fe₂O₃. You adjust it by placing a coefficient of 3 in front of O₂:
[tex]\[
4 Fe + 3 O_2 \rightarrow 2 Fe_2O_3
\][/tex]
- Now, count the atoms again:
- Left side:
- Fe: 4
- O: 6 (in 3 O₂ molecules)
- Right side:
- Fe: 4 (in 2 Fe₂O₃ molecules)
- O: 6 (in 2 Fe₂O₃ molecules)
Now the equation is balanced, with 4 Fe atoms and 6 O atoms on both sides.
Therefore, the correct balanced equation is:
[tex]\[
4 Fe + 3 O_2 \rightarrow 2 Fe_2O_3
\][/tex]
This corresponds to choice A.
